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Author Topic:   377 compresion ????
Dirt Maniac

Total posts: 138
posted February 13, 2003 08:20 PM
what kind of compresion #'s can you put in a 377,steel crank,4340 h-beam rods??

Dirt Full Roller

Total posts: 52
posted February 13, 2003 08:58 PM
I have run 13.2 compresion the last 2 seasons with 4340 crank and h-beam rods.(little m block).

Dirt Maniac

Total posts: 138
posted February 13, 2003 09:32 PM
Was wodering what a GM 400, 4 bolt could take

Dirt Freak

Total posts: 353
posted February 14, 2003 08:27 AM
If it helps we ran a 12.5:1 377 in a 2 bolt GM block and the caps were danceing all over the place. They were actually stuck in place when we tore it down. Defintely should have added 4 bolt caps. I know 2 bolt 400s are supposed to be stronger than factory 4 bolts so in my experience we were about on the limit before adding aftermarket caps.

Dirt Forum Racer

Total posts: 82
posted February 15, 2003 12:38 PM
We run close to 14/1. But this is with a 2 bolt with spayed 4 bolt caps. Stock 4 bolt blocks are weak in the main webs but make good boat ancors. Also by the time you take a stock 2 bolt, install good splayed caps, have all your machining done, you may still have a junk block that is cast to thin, which you would not know unless you have it sonic tested. Now that you have done this and determined the block is good, you have all this work done and monney spent and then the head bolt holes in between the cylinders start to pull out and crack every time you torque the heads. And you HAVE to run studs not bolts. With all this in mind,and the fact you can buy a good aftermarket block for about$1500 I would be saving my monny for a good block. I know it is not in everyones budget, but it pays in the long run. I do have a good 2bolt that has been slayed,377 motor 13.5/1 that has been turned 7500 to 8000rpm for 5 years,knock on wood, but have new good block for next engine, will not use stock blocks again.

Dirt Maniac

Total posts: 138
posted February 15, 2003 07:35 PM
Thanks Guys, Mike

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