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408Dakota
08-09-2009, 10:54 PM
Does any one have any idea how much horse power a stock 360 block will hold for street use? I plan to use a girdle. I am going to run twin turbos with a 4"stroke kit. LA or Mag motor. Which ever is stronger. Thanks for you help.

cordes
08-09-2009, 11:49 PM
I would have no idea. Welcome to the site though!

Directconnection
08-10-2009, 01:03 AM
Engine Builders magazine just did a 600hp buildup on a stock 360 block using highly ported Edlebrock heads and intake. 602 hp on 12.5:1 compression and mediocre head castings is pretty impressive. The used a 4" stroke Scat crank, too. Not sure on how long it would last.... but they did it.

Captain Chaos
08-10-2009, 08:28 AM
The general consensus is that the L.A blocks have more meat in them and tend to take more abuse. The Magnum blocks have split the centers like a 5.0 blocks do. There are girdles for strength if you want to use a Magnum block. I have a friend with an R/T thats running mid-low 10's on a 408 and N2O. Don't know if you've been over there but there is a couple knowledgable people on Dakota-durango.com

408Dakota
08-10-2009, 09:25 AM
Thanks for the info.

Ondonti
08-11-2009, 09:23 AM
why so weak?

mpgmike
08-16-2009, 10:32 AM
I was asking my machine shop a couple of years ago if they had a boring plate for the SB Mopars. He said they did not. I replied that their head guy (the guy that does the heads, not the chief) was running a '70 Duster in the 9's; surely they had a boring plate. Here was his reply (from memory):

"The LA blocks are so rigid that if you bore one with and one without the plate, you won't be able to tell the difference, even bolting the plate on both. The Magnum blocks, on the other hand, are so flimsy that you better not only use a boring plate, but also bolt on the motor mounts, AC/Alt brackets, and anything else that might add distortion. It will matter."

This sort of got my attention. I'd love to utilize the Magnum top end breathing capability while retaining the strength of the LA bottom end.

Mike

Captain Chaos
08-16-2009, 11:28 AM
I was asking my machine shop a couple of years ago if they had a boring plate for the SB Mopars. He said they did not. I replied that their head guy (the guy that does the heads, not the chief) was running a '70 Duster in the 9's; surely they had a boring plate. Here was his reply (from memory):

"The LA blocks are so rigid that if you bore one with and one without the plate, you won't be able to tell the difference, even bolting the plate on both. The Magnum blocks, on the other hand, are so flimsy that you better not only use a boring plate, but also bolt on the motor mounts, AC/Alt brackets, and anything else that might add distortion. It will matter."

This sort of got my attention. I'd love to utilize the Magnum top end breathing capability while retaining the strength of the LA bottom end.

Mike
Thats an interesting observation for sure. I know my machinist complained about the 4 bolt pattern around the bore as opposed to 5 on the big blocks, but bushes the lifter bores on all other make blocks he can for SB Chrysler lifters.

TurbododgePirate
08-19-2009, 10:49 AM
There are some pretty interesting engine builds using LA blocks and magnum heads out there. If you get magnum heads though, don't buy stock, I have seen 6 sets that were all cracked. There are a couple companies that make thicker stronger casting heads, and they aren't too expensive.

Captain Chaos
08-21-2009, 03:03 PM
Clearwater Cylinder Head in Clearwater Fl Has some heads comperable to Mopar R/T heads and RHS I think is the other company making an iron head.