Guys, what CC head would it take to make an older (dish piston) 5.3 11:1 compression ratio? I had this combo before and it was pretty nasty with the setup I had in it and I cant remember what I had the heads milled to. Thanks in advance guys!

 

It would have to be down around a 52cc chamber with a .041 head gasket and I'm still not sure it would be quite 11:1. Milling a set of 706's .030 or maybe .040 would get you close.

 

I have a set of ported 862's which is virtually the same as 706's. Anyone know the dish size of these pistons?

 

I don't know if you can do it will milled heads alone. I calculate a 52cc chamber with .041 gaskets to get a 11.00 static cr on a 5.3 with 8cc pistons. For stock .054 gaskets, you would need a 49cc chamber for 11.07 scr.

 

Engine Size and Compression Calculator

 

3.77 bore for 323 or 3.78 bore for 325

stroke 3.62

Pistion dish is -7cc

stock heads are 61.15 cc

Stock gaskets are 0.051 for ls1 I think the trucks are 0.054 or0.053

I think the max you can mill a set of 862/706 heads is 0.04. the deck surface starts to get weak from to much metal being removed.

For every 0.007 milled is roughly 1cc removed so 0.007*5.7cc=0.0399 milled

61.15-5.7=55.45 cc

This 55.45cc milled 0.04 heads plus 0.03 head gaskets gets you around 10.75CR I would be concerned about piston to valve clearance with a large lift cam. Hope this helps!!!

 

Some 4.8L flat top pistions with 0.03 milled heads and stock 0.051 head gaskets puts it right at 11:1