Just out of curiosity....

Stock 2003 5.3 heads, whats the most they could be shaved to up compression?
and/or thinner head gaskets.?

Does this do bad things with valve train geometry?

raisin

 

I Would Not Go More Than 50 Ths And Put A Shim Under The Rocker Bar The Same Amout U Shaved

 

no one can really say how much can be safely shaved off before you do harm to the heads and turn them in to trash.

you need to take them to a machine shop and have them mic the heads.
this way the machine shop can tell you just how much can be removed and make you a set of balanced heads.
I have always said that no two heads are the same, the machine shop will tell you that you can shave 045 on one and 042 on the other and both heads will have the same compression on all cylinders.

 

02SierraZ71 had .050 taken off his heads; don't know exactly how much compression he ended up with though. Just under a point, maybe? He did have some valve-train issues at first but now his truck runs like a scalded dog!

 

I think TarheelZ is right, every 0.010" is about 0.2 CR change. Valvetrain angle and pushrod length are gonna be your worst enemies. Someone makes altered length pushrods but no custom rocker arms yet.
Good octane gas and some tuning should show decent gains.