What is a 655 head?

[contraption22]

I've read the 655 mentioned in a handful of threads now.

Is this a swirl or G head?

Any specific model years?

Anything particularly special about it?

[Force Fed Mopar]

G-head, came on early carbed cars. Has larger intake ports. If you look at the port size on a intake gasket, that's what size the ports are on a 655. In fact, I'm sure that's why the gasket ports are made that big in the first place, to fit them as well as the rest ;)

[Pat]

Has anyone gone fast with it or is the hype all speculation?

[Force Fed Mopar]

Not sure, The Pope seems to love them, others say all the heads are similar in performance after porting. I'm gonna try one on my next engine build I think.

[4 l-bodies]

Mike and group,
The 655 head has got a terrible short turn (esp. the exhaust). No fixing that without welding. IMO, the only reason they seem to show any promise is that the port volume is already large on the intake. I think of them as a poor mans alternative to a properly ported g-head. I made this comment to Steve Menegon at SDAC and he concurs. I have posted this before, but below is a cutaway drawing showing the changes from the 655 head to the 287/455 casting. Sometimes pics speak a thousand words...
Todd

[GLHNSLHT2]

Terry's bolting one onto his van. Here's the flow #'s of a NOS 655 vs a 782. http://www.turbododge.com/forums/f4/f17/127958-stock-782-vs-stock-655-8v.html

[gvare001]

I have one in the garage and if I ever decide to get back in the hobby this is what I will be using considering that I've used everything else.:D

[turbovanman²]

So has anyone gone fast on one? Results also speak a 1000 words, ;)

[GLHNSLHT2]

Well for years they've been unheard of and talked down about being used at all if they were ever brought up. There's guys out there though that are bolting them on so soon we'll see. Over on TD some guy sold his 655 head for a lonewolf 782. He was all pissed cause his 655 he ported outflowed the $1100 lonewolf head he bought.

[contraption22]

Well for years they've been unheard of and talked down about being used at all if they were ever brought up. There's guys out there though that are bolting them on so soon we'll see. Over on TD some guy sold his 655 head for a lonewolf 782. He was all pissed cause his 655 he ported outflowed the $1100 lonewolf head he bought.

On the same flowbench on the same day?

[turbovanman²]

Well for years they've been unheard of and talked down about being used at all if they were ever brought up. There's guys out there though that are bolting them on so soon we'll see. Over on TD some guy sold his 655 head for a lonewolf 782. He was all pissed cause his 655 he ported outflowed the $1100 lonewolf head he bought.

Not to start another thread but we all know flowbenches are a good tool but don't show the whole picture, especially with boost fed engines.

[ShadowFromHell]

Hmmm.... I think i have one of these laying around. Guess we will have to see how they work out for everyone else.

[boost geek]

http://i91.photobucket.com/albums/k302/boostgeek/100_2517.jpg

[Directconnection]

Well for years they've been unheard of and talked down about being used at all if they were ever brought up. There's guys out there though that are bolting them on so soon we'll see. Over on TD some guy sold his 655 head for a lonewolf 782. He was all pissed cause his 655 he ported outflowed the $1100 lonewolf head he bought.

Those bolting on a 655 casting are also doing many other changes at the same time, so not a good comparison at all.

Flow #s are not the full equation, too. As 5digits used to tell me: "Quality of flow, not quantity" which is true. Turbulence and airspeed mean so much more as that dictates the cylinder filling/scavenging and flow #s just tell the port's capacity at that depression.


Meaning: cfm #s on the flowbench at a glance to the average person tells you that port's capability to flow a certain amount of air at a given depression. Yet, doesn't tell you how the cylinder fills when the piston is at "x" crank degrees with certain valve lift at certain rpm and piston velocities. You can have a head flow a great deal of air, but won't live up to it's potential if the FPM airspeed is not in a certain acceptable range for cylinder filling.

[Directconnection]

On the same flowbench on the same day?

We've all seen the thread on what 2 different flowbenches and operators claim on any given day.

A/B comparos in this thread only, please.

[Force Fed Mopar]

Yeap, the downside to big ports is usually loss of low end air velocity, which equates to less torque in the lower revs. In general theory anyway, obviously there's tons of variables. Port size becomes less of a factor in forced induction engines also I think. How well it flows through the port and into the cyl is more important, since smaller port volume can be made up for with extra boost.

[The Pope]

On the same flowbench on the same day?

Some flow benches flow a ton and then some flow very low. A huge reason I've pushed people to show there % of gain, not CFM numbers. Tyler is an example of some one that shows flow the right way.

LWP head in question was shown to flow less on the exhaust, in % of gain than it was supposed to. LWP of course made up for the deal and there was no conflict, so this shouldn't be a bash LWP thread hopefully.

The guy in question had a 180 CFM 655 and thought he was buying a 192 CFM LWP head. So he sold his poor flowing 655 in his mind and bought the better flowing head. I made a wise crack about it because he was basing his personal flow #'s vs LWP #'s, "you don't really know unless you flow the new head on the same bench". Well he did and the LWP didn't flow nearly as well. The guy bought a head based on flow numbers, which is the wrong thing to do. In the end he sold his 655 and was SOL. This wasn't LWP fault either, but they delt with it :thumb:

The description from Mopar on the 655 is a load of bull. I'm sure they had there reasons but the 655 has a big sweet short turn. The 782 has no short turn, yet everyone seams to like the 782 for reasons that don't exist. The 655 is being used finally in the turbo world on many engines being built this year. Opinions are going to be changing very soon, if you have one I would be keeping it.

[bakes]

Now this is not a good comparison but the head that dick(Boostgeek)has is the sister to the head i put on my Red Glh N/a 2.2 carb 8v (road race car ) that head flowed real good had power till 8k then the lifters would float (had the tach tattle tale pinned at 8.2k) note: this was on a N/a motor not a boosted motor.

[turbovanman²]

The description from Mopar on the 655 is a load of bull. I'm sure they had there reasons but the 655 has a big sweet short turn. The 782 has no short turn, yet everyone seams to like the 782 for reasons that don't exist. The 655 is being used finally in the turbo world on many engines being built this year. Opinions are going to be changing very soon, if you have one I would be keeping it.

So why did SMP use a 782 and why does he recommend a 782 for all out engines?

[The Pope]

Yeap, the downside to big ports is usually loss of low end air velocity, which equates to less torque in the lower revs. In general theory anyway, obviously there's tons of variables. Port size becomes less of a factor in forced induction engines also I think. How well it flows through the port and into the cyl is more important, since smaller port volume can be made up for with extra boost.

http://www.turbododge.com/forums/f4/f17/127958-stock-782-vs-stock-655-8v.html

The 655 pulls away from the 782 at .100" lift and keeps going on the intake

The 655 pulls away from the 782 at .200" lift and keeps going on the exhaust

There is BETTER low lift flow, not worse. More velocity is created at low lift, then at high lift more volume is gained as well. Yet people still think the ports are worse LMAO. The 655 also has a better chamber with a lot less valve shrouding. Sure if your talking an X head vs a Magnum head the small ports out flow the big ports a lot at low lift. So in that case the big nasty ports don't work. That isn't the case here folks, the big ports work better, period. If they cavitated and lost velocity it would show up.

BTW with the boost people run with an 8v why is velocity such a worry? I think you guys can lose a tiny bit of velocity to move a ton more volume lol.

[bakes]

Yeap, the downside to big ports is usually loss of low end air velocity, which equates to less torque in the lower revs. In general theory anyway, obviously there's tons of variables. Port size becomes less of a factor in forced induction engines also I think. How well it flows through the port and into the cyl is more important, since smaller port volume can be made up for with extra boost.

the ports on all are heads (not 16v ) are way under sized from the factory , opening them up brings them we they should have been.

[The Pope]

So why did SMP use a 782 and why does he recommend a 782 for all out engines?

SMP's own 8v race head is completely welded up and has custom shaped ports that aren't ANYTHING like a 782 LMAO. The 655 isn't in production, you have to find a good old 81-82 casting. Then you need a custom built intake to use one, pretty pricy.

The 782 is still sold brand new........ With major porting work done they can flow very well.

If you ran a business porting heads and wanted to sell a new ported head to some one would you push a very rare and hard to find casting? Sure that's great for business :clap:

[The Pope]

the ports on all are heads (not 16v ) are way under sized from the factory , opening them up brings them we they should have been.

:faint:

wholy crap where did you come from :amen: The 655 has smaller ports and valves than a 2.3 Ford 8v. The "big" valves are stock 22R Toyota 8v size valves. But OMG we better not go so big or something bad will happen :bolt:

[bakes]

Dick is putting the 44m intake and large exhast valves in his ( my old head) should be closer !!
Dick and i were looking into 47 mm intake but i would have pushed them way to tight.

[The Pope]

Dick is putting the 44m intake and large exhast valves in his ( my old head) should be closer !!
Dick and i were looking into 47 mm intake but i would have pushed them way to tight.

Depends on the head with me. The 782 cracks up and leaks so bad in the chambers I am afraid to push too far. 46 x 37 on any bath tub head is nice though with enlarging the chambers to the gasket.

[Force Fed Mopar]

http://www.turbododge.com/forums/f4/f17/127958-stock-782-vs-stock-655-8v.html

The 655 pulls away from the 782 at .100" lift and keeps going on the intake

The 655 pulls away from the 782 at .200" lift and keeps going on the exhaust

There is BETTER low lift flow, not worse. More velocity is created at low lift, then at high lift more volume is gained as well. Yet people still think the ports are worse LMAO. The 655 also has a better chamber with a lot less valve shrouding. Sure if your talking an X head vs a Magnum head the small ports out flow the big ports a lot at low lift. So in that case the big nasty ports don't work. That isn't the case here folks, the big ports work better, period. If they cavitated and lost velocity it would show up.

BTW with the boost people run with an 8v why is velocity such a worry? I think you guys can lose a tiny bit of velocity to move a ton more volume lol.

Lol, I had a feeling I was gonna be wrong on that :o hence the "usually" and "in general theory" :eyebrows:

[Force Fed Mopar]

Depends on the head with me. The 782 cracks up and leaks so bad in the chambers I am afraid to push too far. 46 x 37 on any bath tub head is nice though with enlarging the chambers to the gasket.

So that's a safe choice in valve size, in your opinion? (don't worry not gonna pin you down to it, just want your opinion). What would be the max? Or, what is the largest valve available for the G-head?

I have some 44mm 782 intake valves I was thinking to make work in the 655, but If I can go larger, I may just sell them.

[The Pope]

So that's a safe choice in valve size, in your opinion? (don't worry not gonna pin you down to it, just want your opinion). What would be the max? Or, what is the largest valve available for the G-head?

I have some 44mm 782 intake valves I was thinking to make work in the 655, but If I can go larger, I may just sell them.

Don't run the 782 valves in a 655, buy the right length so you don't end up with a keep groove where the follower lands lol.

On a 655 a 46mm intake and a stock exhaust valve wouldn't be a bad Idea. But I am a fan of 44 and 37 as they are far enough apart that I don't worry about them hitting when the valve guides get worn. Race engine? It matters less as they are a low mileage thing, all my cars are street cars..

Saddly I am all the way to the valve on my 655 and the seats are smaller than the bowl still :nod: I spend over half of all of my porting time getting super close to the limit on the seat without damaging them. The 44mm seats after the bowl hog are 40mm.

[boost geek]

I have some 44mm 782 intake valves I was thinking to make work in the 655, but If I can go larger, I may just sell them.

Sell those 782 valves to Bakes, he's looking for a set.

We were looking at valves like this, I forget what the total length is.
(45.7mm & 37.4MM).

http://cgi.ebay.ca/22R-RE-TOYOTA-H-P-STAINLESS-VALVES-EPN_W0QQitemZ380137845832QQcmdZViewItemQQptZMotors _Car_Truck_Parts_Accessories?hash=item5881fb3448&_trksid=p3911.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1215%7C 293%3A1%7C294%3A50

[bakes]

Don't run the 782 valves in a 655, buy the right length so you don't end up with a keep groove where the follower lands lol.

On a 655 a 46mm intake and a stock exhaust valve wouldn't be a bad Idea. But I am a fan of 44 and 37 as they are far enough apart that I don't worry about them hitting when the valve guides get worn. Race engine? It matters less as they are a low mileage thing, all my cars are street cars..

Saddly I am all the way to the valve on my 655 and the seats are smaller than the bowl still :nod: I spend over half of all of my porting time getting super close to the limit on the seat without damaging them. The 44mm seats after the bowl hog are 40mm.

I feel that there is one exception i would put 782 valves in a 655 if i was to use a regrind cam with pt and less shims.
which would allow larger lift cams to be used with out binding.

[bakes]

dick to you have a pic of the closer to fisnish head before the valve are put in?

[boost geek]

The head has been sitting at the machine shop for a while now, havent really finished it yet, so it may still look "rough". It's a 445 head with intakes cut even wider than a stock 655 head. I have a second set of big valves coming, which will go on the real 655 head, then I can see which one I like the best.;)
I also have a 1 piece intake which I'm sure will outflow these heads, maybe not much velocity, but outflow. :D
http://i91.photobucket.com/albums/k302/boostgeek/100_2769.jpg

http://i91.photobucket.com/albums/k302/boostgeek/100_2770.jpg

[bakes]

i think we found some stainless 47-8 mm intakes for a 240 that was close too or was a a 300z cant remember:confused2:

[boost geek]

There is a Nissan motor that uses very similar but somewhat large valves, forget which one it was. You found it once, I'm sure you can find it again...:thumb:

[Juggy]

i keep telling everyone my big valve head is 44 x 37

but actually its 45.xx and 36.8

cant remember where the machinist got the valves, almost positive it was for the toyota motor mentioned previously

anyways, they are currently being run on STOCK seats, only 1 seat was changed because it was damaged.

the 655 has large ports, and flows more cfm.....has a better combustion chamber for more quench.....its a wonder why people are still running swirl heads, guess you guys are looking for emission friendly top end :confused:

if the 655 has such a bad short turn, wouldnt a 445 and 287 be an even nicer head if it was ported out to the 655 status???

[contraption22]

Isn't it much better to raise the port than to lower it?

[Force Fed Mopar]

I feel that there is one exception i would put 782 valves in a 655 if i was to use a regrind cam with pt and less shims.
which would allow larger lift cams to be used with out binding.

I was thinking that too. I will be running a cam also, not sure if it's gonna be my FM475 cam or a roller of some sort. I will also be running the 2.4 lifters and beehive springs, etc.

[GLHNSLHT2]

I think my 995 comp beehives are good to like .550 or .600 lift, how much more do you need? :)

[turbovanman²]

the 655 has large ports, and flows more cfm.....has a better combustion chamber for more quench.....its a wonder why people are still running swirl heads, guess you guys are looking for emission friendly top end :confused:

if the 655 has such a bad short turn, wouldnt a 445 and 287 be an even nicer head if it was ported out to the 655 status???


Why, because 782's are proven to make power. I know I keep saying this but SMP said he tested alot of heads and found the 782 superior for higher boost, something about less spark needed and better combustion. Take it with a grain of salt or ? ;)

[turbo84voyager]

Why, because 782's are proven to make power. I know I keep saying this but SMP said he tested alot of heads and found the 782 superior for higher boost, something about less spark needed and better combustion. Take it with a grain of salt or ? ;)

Simon, we both learned the hard way 782's are a better choice bolted to a 2.5 and in a mini..

I believe the less spark. A 782 has much less of an aggressive timing curve than a G.

[turbovanman²]

Simon, we both learned the hard way 782's are a better choice bolted to a 2.5 and in a mini..

I believe the less spark. A 782 has much less of an aggressive timing curve than a G.

I know, :o lol!

You look at the faster guys, IE Reeves, SMP, Gasketmaster then, all running 782? Coincedence or ? ;)

[contraption22]

I know, :o lol!

You look at the faster guys, IE Reeves, SMP, Gasketmaster then, all running 782? Coincedence or ? ;)

Reeves is running a G head.

[bakes]

I'm currently working on a highly modded 782 (There will be some welding/there going to be a lot of grinding) thats why dick has my old spare g head.

[BadAssPerformance]

Reeves is running a G head.

I'm not fast, but used to run a G head too, but with a 2.2L...

Was SMP a G-head? not that the CC mattered with how big the ports were.

[Pat]

I'm not fast, but used to run a G head too, but with a 2.2L...

Was SMP a G-head? not that the CC mattered with how big the ports were.

I'm pretty sure he was swirl.

[turbovanman²]

Reeves is running a G head.

Hmmmmmm, my bad, I thought was running a Steve M swirl?

[turbovanman²]

I'm not fast, but used to run a G head too, but with a 2.2L...

Was SMP a G-head? not that the CC mattered with how big the ports were.

Swirl, hence why I keep bringing it up, ;)

[BadAssPerformance]

Swirl, hence why I keep bringing it up, ;)

When my PC is back up I'll look for the pics of it... BTW, do you know what cc the CC was?

The MP heads were g-heads, how come? With a bunch of boost does the shape of the CC really matter? Well, yes, to a point.

[turbovanman²]

When my PC is back up I'll look for the pics of it... BTW, do you know what cc the CC was?

The MP heads were g-heads, how come? With a bunch of boost does the shape of the CC really matter? Well, yes, to a point.

I had pics but until I get my computer back, I dont' have them, :(

I know the ports were the size were like tennis balls, :wow1:

[BadAssPerformance]

Huge ports and the CC was modded too

[cordes]

Huge ports and the CC was modded too

I would like to see some pics of different really high HP heads. I recall the posts Simon is referring to. SMP stated several times that the swirl head required less timing to be pulled per lb. of boost and that was one of the reasons he preferred it.

[BadAssPerformance]

I would like to see some pics of different really high HP heads. I recall the posts Simon is referring to. SMP stated several times that the swirl head required less timing to be pulled per lb. of boost and that was one of the reasons he preferred it.

So any head with ports you can roll a golf ball thru running 4 BAR boost on a 2.2L in a sub 2k# car can somehow have the same timing curve as Simon's van running 3 BAR boost thru a 2.5L with mild g-head and stock-ish maifolds on a 3k# toolshed :confused2: Apples, meet Oranges.

[cordes]

So any head with ports you can roll a golf ball thru running 4 BAR boost on a 2.2L in a sub 2k# car can somehow have the same timing curve as Simon's van running 3 BAR boost thru a 2.5L with mild g-head and stock-ish maifolds on a 3k# toolshed :confused2: Apples, meet Oranges.

I'm not certain. I may try to do a search for his posts in those threads to see who he was quoting etc.

[cordes]

Here is a thread in which he makes some statements about his preference.

http://www.turbo-mopar.com/forums/showthread.php?t=1491

This thread has a couple poor quality head pics in it.

http://www.turbo-mopar.com/forums/showthread.php?t=56

[Aries_Turbo]

im pretty sure terry (gasketmaster) was running a lightly ported G head. dunno about the new one though

brian

[turbovanman²]

im pretty sure terry (gasketmaster) was running a lightly ported G head. dunno about the new one though

brian

Ack, your right, he was. His new head is a 655 G-head. I need to write this shiat down or shut up, lol.

[johnl]

Isn't it much better to raise the port than to lower it?


I've ported stuff, works good, no data, but that's my opinion. Here's how I think about it, at least on the intake side -

Envision a port with a 90* turn just before the valve.
That column of air directly hits the wall, not the valve.

Now, tilt the port up so there's a 45* turn.
That column of air now directly hits half of the valve.
The other half of the column of air has to turn, sucked down by the Bernoulli effect/vacuum; the inertia of the mass of the air fights that Bernoulli vacuum so the air cavitates and tears as it passes over the short turn, tumbling down. The lower half of the seat is underpressurized, the upper half is overpressurized.

Now tilt the port up to 0* turn (impossible you say? yes, practically, but imagine a two foot port and 3 foot valve stem and port bend 18" up there, way up there - so the valve stem can run down the dead center of the port).
The column of air now hits the radius/seat of the valve square on.
No cavitation or tumbling over a short turn.
No compression or tumbling into a long turn.
No turn at all.
Think of top fuel dragster ports - as straight as possible.

So, to my mind, the object of porting on the intake side is to fool the air into behaving as if it is not turning, to equalize pressure around the radius of the valve seat.

That's the theory, IMO, for the hump in floor of the later (non 655) ports, as in the picture Todd posted, the higher floor, near the short turn, fools the air into acting as if the port was tilted upwards, closer to parallel with the stem, giving the air a better angle of attack on the opening valve radius/seat.

[boost geek]

Hey Simon, if 782's were so good, why did you go 16 valve? For the amount of $$$ you have in your engine, spare heads, parts, you could have had a killer 8 valve.
I mean this in a nice way, 'cus your still my bud. :p

[turbovanman²]

I've ported stuff, works good, no data, but that's my opinion. Here's how I think about it, at least on the intake side -

Envision a port with a 90* turn just before the valve.
That column of air directly hits the wall, not the valve.

Now, tilt the port up so there's a 45* turn.
That column of air now directly hits half of the valve.
The other half of the column of air has to turn, sucked down by the Bernoulli effect/vacuum; the inertia of the mass of the air fights that Bernoulli vacuum so the air cavitates and tears as it passes over the short turn, tumbling down. The lower half of the seat is underpressurized, the upper half is overpressurized.

Now tilt the port up to 0* turn (impossible you say? yes, practically, but imagine a two foot port and 3 foot valve stem and port bend 18" up there, way up there - so the valve stem can run down the dead center of the port).
The column of air now hits the radius/seat of the valve square on.
No cavitation or tumbling over a short turn.
No compression or tumbling into a long turn.
No turn at all.
Think of top fuel dragster ports - as straight as possible.

So, to my mind, the object of porting on the intake side is to fool the air into behaving as if it is not turning, to equalize pressure around the radius of the valve seat.

That's the theory, IMO, for the hump in floor of the later (non 655) ports, as in the picture Todd posted, the higher floor, near the short turn, fools the air into acting as if the port was tilted upwards, closer to parallel with the stem, giving the air a better angle of attack on the opening valve radius/seat.

Think newer sportbike, you can look directly down into the cylinder, :amen:



Hey Simon, if 782's were so good, why did you go 16 valve? For the amount of $$$ you have in your engine, spare heads, parts, you could have had a killer 8 valve.
I mean this in a nice way, 'cus your still my bud. :p

There not that good, they don't flow. 16 valves kill in flow and I would have more into a 8 valve setup and still not have the midrange and grunt I do now, :nod:
I have a bad casting, could have happened with an 8 valve head if I had spent money to get it ported, then have it go bad, :(

[bakes]

When my PC is back up I'll look for the pics of it... BTW, do you know what cc the CC was?

The MP heads were g-heads, how come? With a bunch of boost does the shape of the CC really matter? Well, yes, to a point.

I always thought that is was because the CC had more cc's lowering compression allowing higher boost with the Cal's of that time period .

[contraption22]

Hmmmmmm, my bad, I thought was running a Steve M swirl?

Nope, He's running a Steve M. G-head.

[puppet]

I've ported stuff, works good, no data, but that's my opinion. Here's how I think about it, at least on the intake side -

Envision a port with a 90* turn just before the valve.
That column of air directly hits the wall, not the valve.

Now, tilt the port up so there's a 45* turn.
That column of air now directly hits half of the valve.
The other half of the column of air has to turn, sucked down by the Bernoulli effect/vacuum; the inertia of the mass of the air fights that Bernoulli vacuum so the air cavitates and tears as it passes over the short turn, tumbling down. The lower half of the seat is underpressurized, the upper half is overpressurized.

Now tilt the port up to 0* turn (impossible you say? yes, practically, but imagine a two foot port and 3 foot valve stem and port bend 18" up there, way up there - so the valve stem can run down the dead center of the port).
The column of air now hits the radius/seat of the valve square on.
No cavitation or tumbling over a short turn.
No compression or tumbling into a long turn.
No turn at all.
Think of top fuel dragster ports - as straight as possible.

So, to my mind, the object of porting on the intake side is to fool the air into behaving as if it is not turning, to equalize pressure around the radius of the valve seat.

That's the theory, IMO, for the hump in floor of the later (non 655) ports, as in the picture Todd posted, the higher floor, near the short turn, fools the air into acting as if the port was tilted upwards, closer to parallel with the stem, giving the air a better angle of attack on the opening valve radius/seat.

Well, sort of. Air flow takes the shortest path. It's at the short turn were velocity will be the highest as opposed to along the roof. Raising a port floor means there has to be a bigger short turn radius. Air flow will hug that turn and gain speed. That's better than little to no short turn with flow acting like a column slamming into the bowl.

[BadAssPerformance]

I always thought that is was because the CC had more cc's lowering compression allowing higher boost with the Cal's of that time period .

The cals have a set boost and MP didnt really advertize boost control...

I was told that it was because the G head has a bit more meat to remove... the folks making the Mopar race team heads would use the G heads for race engines... the MP heads were toned down versions.

[The Pope]

Well, sort of. Air flow takes the shortest path. It's at the short turn were velocity will be the highest as opposed to along the roof. Raising a port floor means there has to be a bigger short turn radius. Air flow will hug that turn and gain speed. That's better than little to no short turn with flow acting like a column slamming into the bowl.

The floor of a 655 on the short turn is taller than the short turn on a stage 6 and Edelbrock RPM head. I don't mean by scale, the distance from the seat up to the turn is taller.

:closed_2:

A big reason the 655 is different is that the ports are raised higher from the gasket. Then they don't turn the roof in fast pinching off flow, they have a nice tall clear flow increasing ceiling. Koffles Place in 1986 ran a 2 door L body, carbs, an auto trans, and 13.4 @ 104. Side draft intake opened up to a 655 and a Crane .610" lift cam. No bottle, no turbos, 2450 lb race weight. Completely unheard of today NA with an auto trans over 20 years later. Same guys took Pro Stock from Gliden not long after. Years later people still won't try it or even actually look at it in person before making assumptions. :confused: The ONLY head Mopar EVER MADE for the 2.2 in 8v that flows PAST .600" with stock shaped ports, fools. Oops I forgot, with TD people .600" + flow is a bad thing lol.:thumb:

[Force Fed Mopar]

So, in your opinion, what should be done (porting wise) to a 655? Anything? Gasket match and flash removal?

Also, how important is valve size actually? I think you said that the valve seat is a bottleneck?

Hopefully gonna start working on mine here soon, just need to get an idea of what I'm aiming for.

[Force Fed Mopar]

On a 655 a 46mm intake and a stock exhaust valve wouldn't be a bad Idea. But I am a fan of 44 and 37 as they are far enough apart that I don't worry about them hitting when the valve guides get worn. Race engine? It matters less as they are a low mileage thing, all my cars are street cars..

Saddly I am all the way to the valve on my 655 and the seats are smaller than the bowl still :nod: I spend over half of all of my porting time getting super close to the limit on the seat without damaging them. The 44mm seats after the bowl hog are 40mm.

So you couldn't run a 47mm intake? Especially not w/ a 37mm or 39mm exhaust? :) I was looking at a pic of some 44mm int/37mm exhaust and it looked like that was just about as close as you could get w/o hitting.

You say, a 46mm int and a stock exhaust might work?? So are you saying you don't think the stock exhaust valve restricts the flow much? I would say that depends on the amount of boost you run, but that's just my un-educated guesstimation :eyebrows:

[Force Fed Mopar]

Bump for answer to above question ^^ :)

[Force Fed Mopar]

After taking a few months off, Im getting back in the garage to get my cobra running right. Im running a stock 302 out of a 90 mustang, stock heads intake new stock radiator no ac. Ive got the heads off the car due to what i believe was a bad head gasket. Im looking for recommendation on head gaskets, intake gaskets. also i have the stock head bolts and i was wondering if i need to replace them or are they reusable? thanks

And how exactly is that even remotely related to this thread? :confused2::confused::focus:

[Aries_Turbo]

And how exactly is that even remotely related to this thread? :confused2::confused::focus:

he was a Latvian spammer. :) banned now.

[The Pope]

So you couldn't run a 47mm intake? Especially not w/ a 37mm or 39mm exhaust? :) I was looking at a pic of some 44mm int/37mm exhaust and it looked like that was just about as close as you could get w/o hitting.

You say, a 46mm int and a stock exhaust might work?? So are you saying you don't think the stock exhaust valve restricts the flow much? I would say that depends on the amount of boost you run, but that's just my un-educated guesstimation :eyebrows:

You need to get to 46mm to get out to the bowl. You don't want the speed bump there. The difference between the big valve and the stock valve is pretty small in flow and the increased cylinder pressure from more intake will force the exhaust out harder. So on say a NA V8 they used to do this with the big blocks to add more bottom end, the early closed chamber heads. In this case your trying to get more cylinder pressure with boost. SHADOWs setup, big cam and intake with poor exhaust flow is an example of great intake flow and poor exhaust working to make a ton of cylinder pressure. The 655 should increase this. Terry is running a big valve 655 and the basically the same exhaust and loves it. The only draw back could be shrouding, things are getting tight at 44mm. The plan is going stock on the exhaust to make room for more intake without shrouding...

[Force Fed Mopar]

Will deshrouding hurt anything w/ a stock valve? I ask, because I've already deshrouded both intake and exhaust in one combustion chamber on my 655, so I kinda have to do the other 3 now too... :)

[boost geek]

Where can you get 46mm valves? Are they Toyota valves?

[Force Fed Mopar]

Where can you get 46mm valves? Are they Toyota valves?

I haven't found any yet. Closest I've found is the L28 Nissan (45mm) and the 2TC/3TC Toyota (47.1mm).

[boost geek]

Is the 47mm length the same? I'm sure you can fit them in with deshrouding. ;)

44/36.8 on the left. Lots of room after deshrouding.
http://i91.photobucket.com/albums/k302/boostgeek/100_3343.jpg

[bakes]

Is the 47mm length the same? I'm sure you can fit them in with shrouding. ;)

44/36.8 on the left. Lots of room after deshrouding.
http://i91.photobucket.com/albums/k302/boostgeek/100_3343.jpg

Dam dick will you finish that head off!!! dont make me come all the way back out there to do the work for ya!!!!!

[boost geek]

I have till next spring. First gotta get a head for the Sundance done. :)

[turbovanman²]

I have till next spring. First gotta get a head for the Sundance done. :)

Dude, fix/get the bloody SC done first, for crying out loud. :mad:

[Force Fed Mopar]

Is the 47mm length the same? I'm sure you can fit them in with deshrouding. ;)


Yes, that's why I posted them :) Both the L28 and the 2TC/3TC valves are available from Ferrea. Got this info off IPP's site.

Sizes are in this order: Head dia, stem dia, stem length, tip length
L28 valves
F1841P E 35 mm 8 mm 115.25 mm 3 mm 20° Flo Stock size.
(Super Alloy)

F1842P E 36 mm 8 mm 115.25 mm 3 mm 20° Flo 1mm oversize.
(Super Alloy)

F1839P I 44 mm 8 mm 114.3 mm 3 mm 20° Super Flo Stock Size

F1840P I 45 mm 8 mm 114.3 mm 3 mm 20° Super Flo 1mm oversize

2TC/3TC/20R/22R valves
F1435P E 38mm 8mm 113.3mm 4.6 19° Super Flo-Toyota 20R

F1433P E 39mm 8mm 108.9mm 5 19° Super Flo-Toyota 2TC-3TC

F1431P E 39mm 8mm 112.2mm 4.6 19° Super Flo-Toyota 22R

F1434P I 44mm 8mm 108.2mm 5 R 8.3 mm Super Flo-Toyota 2TC-3TC

F1436P I 45mm 8mm 115.4mm 4.6 R 8.3 mm Super Flo-Toyota 20R

F1432P I 47.1mm 8mm 113.4mm 4.6 R 8.3 mm Super Flo-Toyota 22R

[boost geek]

Dude, fix/get the bloody SC done first, for crying out loud. :mad:

Don't get your knickers in a knot.:) The Sundance has had a habit of chucking a rocker due to a worn guide. Don't worry, I'll be there for spring time. Gonna sell some stuff in the next couple weeks so I can get a purple 4 puck. ;)

Nice valve info! I saved it for reference.:thumb:

[turboamx]

Are you able to drill the three extra holes for the water cooling inbetween the cylinders like the 782 heads? Should not be to hard to do! I have a couple of these heads and really like them. Does the #4 collant mod help this head also it would appeaar so by design.

[The Pope]

I would be grinding and deshrouding the block with a chamber cut out to the gasket... Like adding a 360 head to a 273, you need to cut the top of the bore out. Just of course measure for your top right to stay away from it. But you also need to deal with the block for max flow, our top ring is almost a 1/4" down..

[Force Fed Mopar]

I deshrouded mine back to the fire ring on the ends (closest to the valves). Think I need to grind the block then?

http://www.turbo-mopar.com/forums/attachment.php?attachmentid=19260&d=1260759811

[puppet]

What? ... I'd think you'd be leaving the piston crown and top ring pretty vulnerable by working the bore larger. I doubt you'd see any increase in flow either at the lift it would take the valve to even get near the cylinder.

[boost geek]

I would lay a used h.g. on the head with a small bolt through the dowel holes to prevent a run away die grinder. You can't cut past the fire ring that way either.

[OmniLuvr]

de-shrouding the block is an old school technique, and it works awsome! if we had a bigger bore engine this wouldnt be important, but if your chamber overlaps the bore, that is no good for flow (but only for intake, not exhaust). there is math to figure out the proper depth and width, il see if i can find it, there was an article on this in "engine masters" magazine.

[puppet]

My machinist chamfers the bores out to the gasket. If the bore isn't opened out to the gasket already ..sure, but you can't go beyond that.

[turbovanman²]

I'll have to look at that for my TIII, it might benefit.

[cordes]

My machinist chamfers the bores out to the gasket. If the bore isn't opened out to the gasket already ..sure, but you can't go beyond that.

I'll be honest. Going to a machinist for this would be the only way I would do it. I just wouldn't want to mess up the bore with a die grinder. It is a lot more expensive to fix the block than it is to get a new head if I"m doing my own work there.

[The Pope]

commen sense folks. Your only very slightly removing material. The block edge is a wopping 1/16" at most. You can mark the block and do a light chamfer real easy and yes the gasket is bigger than the bore. Clearly your not going down to the top ring at TDC, not even half that far. But if you completely cut your chambers to the gasket you don't want to have the bore edge cause issues.

Really old mod done by cave men and 3/8 drills. Even doing it with a ridge reamer above the rings isn't that bad. I'm sure you guys can handle it without digging too deep lol.

This subject has never come up here? Kidding?