Going from 806 to 706 heads
#1
Going from 806 to 706 heads
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!
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!
#2
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