im looking to bump up compression on 5.3 / im gonna be running full P&P 243's with ferrea 6000 series 2.000 /1.055 valves. . . flat top pistons/ 224R cam, .581lift, on a 112 Lsa.stock rockers/ i was looking for 56-60CC how far down do i have to Mill . what's the lowest i can go w/out having PVC or flycutting piston's,in addition how much does the pushrod change.?

 

The better way is too run a thinner head gasket. You still may want to mill too. What kind of compression are you looking for?

 

measure your PTV now...and then subtract for milling, also what gaskets are you running now?

Chad

 

.0065" per cc. .030" will put the chambers right at 60cc's. I wouldn't mill much more than that and I would run GM MLS gaskets @ .051" thick. Your PTV clearance will be close on the intake .060-.080" or so. The main thing you have to worry about is your intake manifold not lining up properly if you mill much more than .030" off your heads. You should always measure for proper pushrod length with a pushrod length checker.

 

im gonna run stock gasket's....

 

Taking .010" off of the head gasket will gain you more compression than taking .010" off of the head. Plus you'll have some added quench benefits. And you wouldn't have to cut the heads as much which makes it easier to resell if need be or allows you to cut a little more if they needed cleaning up in the future.

 

so what head gasket do you all sugest to run. im gonna mill 0.30 off my 243's . . im gonna be set at 60CC if i run different gasket would it bump up the compression even more?

 

I had mine milled .025 and run a .051 MLS gasket and I'm right at 11:4-11:5, but I have -2cc valve reliefs.

 

first off need to measure and record current ptv.
then decide what scr needed.
pr length need to be verified after heads have been milled and new gaskets.