Help with pushrod length!!

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Apr 26, 2006 | 09:27 PM

Trans Am Kid

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Staging Lane

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From: Bedford, TX

Help with pushrod length!!

I have a set of GM performance parts ls6 heads milled .050, cometic .041 head gaskets and TSP 231/237 cam, what length pushrods do I need, and what will my compression be?

Apr 26, 2006 | 09:29 PM

SUX2BU

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From: DFW, TX

Most aftermarket cams are .100 smaller on the base circle so you would need a .050 longer pushrod. BUT since your heads are milled .050. YOU should use stock length pushrods.
If you want to know EXACTLY measure your cams base circle.

Apr 26, 2006 | 09:35 PM

Ksett

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Are you sure their milled .050, that seems like a lot. Do you know the -cc's of the valve reliefs?

Apr 26, 2006 | 09:36 PM

SUX2BU

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From: DFW, TX

Quote:

Originally Posted by Ksett

Are you sure their milled .050, that seems like a lot. Do you know the -cc's of the valve reliefs?

i think GMPP heads are actually milled .055".

Apr 27, 2006 | 09:09 AM

Trans Am Kid

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Staging Lane

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From: Bedford, TX

-4cc valve reliefs

Apr 27, 2006 | 10:17 AM

Xtnct00WS6

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From: Sterling VA

FWIW...I'm almost postitive that TR's cams are about .030 smaller on the base circle. The TR224 on 114 is anyways. I think .100 for the average decrease is a bit large.

Apr 27, 2006 | 12:35 PM

GuitsBoy

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Yeah, you need to know the base circle difference. Theres a .020 discrpency between factory (7.380) and aftermarket (7.400) pushrods. And your gasket brings you .011 closer as well, so if you had a .050 difference in base circle radius youd still be .031" deeper than stock preload. Most manufacturers suggest that you have less preload than stock. Id probably go with 7.350 pushrods and run .019" under stock preload. Or youll do fine with 7.375 pushrods and running .006 over stock preload. That being said, my setup is .011 over stock preload and it runs well. No problems with lifter pumpup.