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Old 01-06-2013, 03:51 PM
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Quote:
Originally Posted by newboldspeed View Post
Just thought that forged pistons would be noisier running than hydro.....
I have read that hydro break like glass (detonation)
But hopefully not going their.
Cheers chap
First, let's get the nomenclature correct. What you're referring to, I think, is hypereutectic (High-per-you-tech-tick) pistons that use more silicon in the alloy than standard cast pistons. Hypers are still cast, but the material they're cast from makes them a little tougher than cast pistons.

Detonation will break or melt pistons no matter what they're made of. Think of it as swinging a sledgehammer down onto the piston crown or holding a cutting torch flame in the middle of the piston crown. Something is gonna give. If you have detonation under control, you could use cheapo cast pistons and have them last forever. It's all in the tune.

Here are some basic recommendations from Blower Drive Service....
Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service
Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service
Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service
Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service
Blower Drive Service: We Deliver Horse Power! - Blower Drive Systems, Blower Kits, Blower Cams, Custom Carb Service

By looking at the tech charts, you can see that a small bore 6-71 that is underdriven by 5% on a 327 CID motor will make 7 lbs of boost. Looking further at the charts, you will see that the maximum static compression ratio you should use for 7 lbs on pump gas is about 8.0:1.

It appears to me that you have not thought this combination through completely. With 64cc heads, I cannot find a suitable dish size in a 327 piston. Largest dish I find is 13cc's (KB158 hyper) and that will make 9.0:1 in a 327 with 64cc heads. You may be able to have Ross or one of the other manufacturers make 327 8.0:1 pistons for you, but plan on taking out a loan to pay for them. You'll need a 25cc dish to reach 8.0:1 with 64cc heads, or you could change to 76cc heads and do it with a 327 flat-top piston.
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