Ported 5.3 heads and CR
 

I had some 5.3 heads ported and milled .030 and I am getting ready to install them. What CR am I looking at with OEM gaskets. Is there thin gaskets for a small bore like the 5.3, I thin it' a 3.9x? I want to get 10.5:1. How can I achieve that?

I'm have this formula that I seen on a head info page mabey it'll help you out somehow.

Simple milling math:

You have a stock 66cc chamber and you want to get down to 63cc.

66-63=3. You have removed 3cc's
.007x3=.021 So to get your chamber down to 63cc, you have to mill the head .021

You can do the reverse, say you want to mill a head .030 to figure out how many cc's that removes you take .030/.007=4.28. Milling a stock 5.7 head .030 puts the chamber at 62 cc.

Now you will have to input your own info in there and see if that helps.

If you are putting the heads on a 5.3 you need to use a 0.040 thick gasket to get 10.45:1CR.

cometic makes a .040 for a small bore I thought.

Would I have valve to piston clearance issues with .030 and 0.040 gaskets? I have a 220R cam with .581/.581 lift and I will be using 7.35 push rods.

Curious to why you didnt look at this before you had the heads milled?

Because I know .030 on a stock gasket is safe, but I want to know who has done more and what set up worked (example, lift mill and or gasket) I think from common knowledge if they go with more lift or the same pushrod problems may arise. You can measure, but there is valve float issues. So is .030 the max on a 5.3 head on a truck?

You are asking questions about compression ratios and PTV clearances after you milled the heads. Just seems like those question should have been asked before milling. And yes, .030 milling is common.

I'm sticking to .030 and stock gasket, but I am just curious. Is that cool? Thanks Bro..

stock 5.3 heads are 62ccs. not 66. stock LS1 heads are 66ccs. mill them .030 and you will be near 59ccs. with a .040 think and 4.0" bore gasket, you will be at 11.54:1 static compression.....which is alot on pump gas in a heavy truck.