9T8Bird

I have a 98 Ls1 with the perimeter bolt heads and found a set of 706 heads, valve covers and coil brackets today and picked them up. I've done a lot of research here and know that I'm increasing compression, but i want to know just how much without any milling of the 706 heads and stock head gaskets. I have found mixed reviews that my 806 head makes anywhere from 9.5:1 to 10:1 compression. So how do i tell what CC my 806 heads are its either 66 or 69 CC?
Any other advice other than ls1 intake valves and porting on these heads? Will there be a noticeable gain from the 806 heads? I have full intake, ls6 intake, header back exhaust and a Mail Tune by frost. Thanks all!

wildcamaro

iTrader: (15)

Stock compression on ls1 is around 10.4:1...706 will bump you up towards 11:1 BUT those heads have small valves and ports then the ls1 head...would have been better off milling ls1 heads OR getting bigger valves and port job on the 706 heads

9T8Bird

Thanks, I was planning on having them go to texas speed for CNC and ls6 valves before going onto my 98.