How much power can a Pre-Common Block handle?

[tvanlant]

I was considering switching to a common block in my 87 GLHS since I have the engine out. But with a little more research, its going to cost more than I really wanted to spend to do the swap. Thedodgegarage says that the pre-common block starts to flex at 250 hp. I don't know what hp levels I'm at, but I will give a list of modifications so you can get an idea. Keep in mind that this car is my daily driver and gets run at full throttle daily, and is taken and beaten hard at the track on weekends.

With that said, let me know your opinion on the pre-CB and/or if you know of others who have had success/failure with the pre-block.

Shortened list of modifications:

Forged Venolia Pistons
T2 Rods
Ported 782 Head
'88 Roller Cam
stock turbo w/ .63 Exhaust Housing @ 20 PSI
Treadstone intercooler w/ Spearco core
52mm Throttle body
+20% Injectors
255 lph fuel pump, AFPR
MP Stage II logic Module
free flowing exhaust
A555 transmission, beefed up
BF Goodrich Drag Radials

[turbovanman²]

With the stock turbo, you'll make around 250 whp, so you'll be fine. If you plan on going with a bigger turbo and more power, you might want to consider upgrading to a CB but many others have used Non-CB's at higher levels and done ok.

[tvanlant]

Any other opinions? I see on TD.com that Bryan is running 34 psi and 11s on a pre-common block.

[tvanlant]

This is a quote from Gary Donovan's site:
"A common block is a must for any engine making over 250 hp for any length o time otherwise broken main caps or crankshaft will be the result."

The thing that worries me is "for any length of time." Since it is my DD.

[GLHSKEN]

Haven't answered because I answered you in another thread. Bryans car is NOT a dd. It is a strip beast. Gary's advice is for safety.

["Top Fuel" Bender]

Not to curse myself but I 've had my '85 block at 300+ Bhp for 8+ years now
Just in the past year have I've been experiencing head lift problems
I am running a forged crank and arp stud everything with a lot of luck
And definetly not a daily driver
If / When I do it over again I'll have a CB w/ a non forged crank
If you got the motor out and plan on keeping it switch over

[Lugert]

My car was a Daily driver until I put the new motor in it.

When running the STOCK Long Block from valve cover to oil pan:
337 whp, 34 psi and mid 11's, Street Legal, Registered and Insured with Current Plates.
(The 11.52 times were with Slicks)

Add Big Turbo, Big Intercooler and Lots of fuel.

Not too many people running around with Cast pistons at that level.

I do not see a need to go to a common block if you are going to keep it under 300 whp.

[BadAssPerformance]

Keep in mind vehicle weight as well. An engine/drivetrain making 250HP will work less pulling a lighter vehicle...

[johnl]

My car was a Daily driver until I put the new motor in it.

When running the STOCK Long Block from valve cover to oil pan:
337 whp, 34 psi and mid 11's, Street Legal, Registered and Insured with Current Plates.
(The 11.52 times were with Slicks)

Add Big Turbo, Big Intercooler and Lots of fuel.

Not too many people running around with Cast pistons at that level.

I do not see a need to go to a common block if you are going to keep it under 300 whp.

Bryan - love the cast pistons part - looked at your Shadow pic/description. Nice. Could you please post some pics of your frame ties/reinforcement?

[looneytuner]

There is an engine recycler in North St. Louis (Wellston) where you can pick up a cb for about $50. They tear down engines for crappy engine rebuilders (jasper and Shreves) If your starting from scratch, Why not go better. Looking at the two different blocks side by side, you can see the dif.

[tvanlant]

I'll have to look into that if my pre-CB fails, but for now, I'm going to give it a shot. Whats the worst that could happen? (as long as the destructo doesn't hurt my pisons).

[cordes]

I'll have to look into that if my pre-CB fails, but for now, I'm going to give it a shot. Whats the worst that could happen? (as long as the destructo doesn't hurt my pisons).

I am in pretty much the same boat as you are. I plan on putting out over 300WHP, so you wont be the only one hoping to keep things together.

[Lugert]

Bryan - love the cast pistons part - looked at your Shadow pic/description. Nice. Could you please post some pics of your frame ties/reinforcement?

I would be more than happy to post pictures of the frame ties and cage.
I should be getting the car out of storage this weekend.

-Bryan

[8valves]

I would be more than happy to post pictures of the frame ties and cage.
I should be getting the car out of storage this weekend.

-Bryan

I thought you sold your car?

Aaron Miller

[Lugert]

I thought you sold your car?

Aaron Miller

Nope. Still here in the garage tucked away.

Hopefully soon I will have enough time to work on it.

Been busy with the vinyl making. I am sponsoring 4 race cars this year so far, I think I have one more in the works, but time will tell on that one.

[johnl]

I would be more than happy to post pictures of the frame ties and cage.
I should be getting the car out of storage this weekend.

-Bryan

Thanks, I'll be waiting.

[tvanlant]

Its been a while and just to follow up on this thread so maybe future readers with the same questions will know....

I have been running my pre-common block engine for 10 months now and its still holding up. I used the stock cast crank and ARP main studs. It's daily driven and see multiple WOT 20 psi passes each day, and has seen several 12 second passes.
Super 70 will be coming soon, so we'll see how it holds up to that.

[mo' parts]

Its been a while and just to follow up on this thread so maybe future readers with the same questions will know....

I have been running my pre-common block engine for 10 months now and its still holding up. I used the stock cast crank and ARP main studs. It's daily driven and see multiple WOT 20 psi passes each day, and has seen several 12 second passes.
Super 70 will be coming soon, so we'll see how it holds up to that.

was this with the stock garret? i would be happy to see some 12's with my omni and set-up in sig

[tvanlant]

How in the world did you ever fit a TBI header in your omni?
That is with the stock turbo (110K miles) but with a .63 exhaust housing bolted on. That is also with BFG T/As. The turbo is huffin pretty hard to supply what the head can flow, though. After a full run, the hot side intercooler pipe is almost too hot to touch!

[BadAssPerformance]

was this with the stock garret? i would be happy to see some 12's with my omni and set-up in sig

Should be able to do it with an Omni for sure.

Stock Garret, '87 T1 short block, and mostly stock everything else got my full weight Shadow in the 12's

http://www.turbo-mopar.com/forums/showthread.php?t=7538