6.0 heads and what they do to the CR
Sep 26, 2004 | 11:47 PM
#1
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From: Armpit of East TX
6.0 heads and what they do to the CR
Here's a thread from the internal section about this very subject on a 5.3.
https://ls1tech.com/forums/showthread.php?t=219847
https://ls1tech.com/forums/showthread.php?t=219847
Sep 27, 2004 | 12:03 AM
#2
The math is:
Cyl Volume + Gasket volume + Chamber volume / Gasket volume + Chamber volume = Compression Ratio
Its not hard to find the values needed to calculate this yourself. You need to know the formula for the volume of a cylinder, which is: (1/2 bore x PI) squared x stroke. Then you can find the exact volume of the cylinder and gasket volume.
Cyl Volume + Gasket volume + Chamber volume / Gasket volume + Chamber volume = Compression Ratio
Its not hard to find the values needed to calculate this yourself. You need to know the formula for the volume of a cylinder, which is: (1/2 bore x PI) squared x stroke. Then you can find the exact volume of the cylinder and gasket volume.
Sep 27, 2004 | 12:32 AM
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From: Sacramento, CA
Not counting gasket differences you should be at 8.7:1 CR on a 5.3L motor with the 6.0L heads. With the thicker 6.0L gaskets you could be bewteen 8.5:1-8.6:1. I just say somewhere in there. It's close enough anyway. 
Sep 27, 2004 | 01:47 AM
#6
not with the dish in the 5.3 pistons, what you would need is the flat top piston from the 4.8 to get it up to 9-1.
8-1 is perfect for a supercharger or a big shot of noss, i know it sounds funny
but the higher your compression the less you get out of it, the lower the bigger the gain.
back when i was a teenager the top dog on drag was a grandtreno with a M351/400, had a comp of 8-1 and a 250 horse wet shot of noss, nothing special about the motor it was all stock but the holly carb, every body else running chevys built up their motors running 11-1 or 12-1 even up to 14-1 with shaved heads, steel gaskets, headers, big cams, and raised pistons but when they added the noss it blew to much pressure in the cylinder, for some reason they just could not get in their thick heads that inorder to run the big shots they needed to lower the comp, i know i saw allot in auto shop when they brought them in to work on it, pistons drove down on the rod or the head hanging on by one bolt, even seen a few with holes in the motor big enough to hold a basketball, the worst one i saw was a camaro with a big hole in the hood were the head shot through, that was scary.
8-1 is perfect for a supercharger or a big shot of noss, i know it sounds funny
but the higher your compression the less you get out of it, the lower the bigger the gain.
back when i was a teenager the top dog on drag was a grandtreno with a M351/400, had a comp of 8-1 and a 250 horse wet shot of noss, nothing special about the motor it was all stock but the holly carb, every body else running chevys built up their motors running 11-1 or 12-1 even up to 14-1 with shaved heads, steel gaskets, headers, big cams, and raised pistons but when they added the noss it blew to much pressure in the cylinder, for some reason they just could not get in their thick heads that inorder to run the big shots they needed to lower the comp, i know i saw allot in auto shop when they brought them in to work on it, pistons drove down on the rod or the head hanging on by one bolt, even seen a few with holes in the motor big enough to hold a basketball, the worst one i saw was a camaro with a big hole in the hood were the head shot through, that was scary.
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