Heads for a small bore?

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Sep 14, 2014 | 01:06 PM

Fat Jesus 808

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From: Creswell, Oregon

Heads for a small bore?

Having a hard time finding any decent info on what heads with what valve size work well for a 3.800 bore. Looking at either cnc'd oem castings or aftermarket castings. Any help is appreciated. I have searched, and maybe i just fail at it

Sep 14, 2014 | 01:38 PM

KCS

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From: Conroe, TX

2.00"/1.55" is a good start, but 2.02"/1.59" will fit.

Sep 14, 2014 | 01:55 PM

Fat Jesus 808

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so a prc 2.5 6.0L head would be a decent choice if im looking for a bigger combustion chamber to lower compression?

Sep 14, 2014 | 02:25 PM

KCS

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Quote:

Originally Posted by Fat Jesus 808

so a prc 2.5 6.0L head would be a decent choice if im looking for a bigger combustion chamber to lower compression?

Yeah sure. I did a set of heads for a guy with 2.02"/1.59" valves that went on a twin turbo 4.8L. On "low boost" he made over 650whp in a truck and the heads weren't even ported. Literally, just a valvejob for the larger valves.

Sep 14, 2014 | 03:29 PM

Fat Jesus 808

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I just figure by the time i buy 317s, a spring kit, clean up the ports and blend stuff and freshen the heads, im well over half way to buying a set of those

Sep 14, 2014 | 09:10 PM

Violence.z06

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RHS has a 2.1 int / 1.575 ex valve head for the 3.9 bore motors.

http://www.racingheadservice.com/rhs...r-ls1-ls2html/

Sep 14, 2014 | 09:44 PM

Fat Jesus 808

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From: Creswell, Oregon

would prefer to stay cathedral as i'll stick with my ls6 manifold, and im not sure of a 2.1 int valve on a 3.800 bore

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Sep 14, 2014 | 09:59 PM

MR ELKY

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From: Conroe ,TX

Im with KCS on this I think the 2.00 / 1.55 is what you would need , No use in trying to put a big valve big runner on a small bore / small stroke wont flow it and the velocity will suck , You didnt say if it was going to be NA or boosted , But honestly if its a 5.3 or 4.8 one of the smaller combustion chambered heads and smaller runner heads would work best .

Sep 14, 2014 | 10:18 PM

#10

American Psycho

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Check out the TSP 5.3l heads

Sep 15, 2014 | 08:42 AM

#11

Fat Jesus 808

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From: Creswell, Oregon

It's going to be boosted. I would prefer a larger cc combustion chamber to help lower the compression. Most forged 5.3 pistons are not very dished

Sep 15, 2014 | 09:00 AM

#12

garygnu

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you don't want the valve to close to the cylinder wall ,it will hurt flow .small valves will work great in a boosted engine .the 241 head is a 67cc chamber .you can find the 317 heads for a good price .only get the cam after your heads are done and flowed ,and you have decided on what turbo or blower you want.