53bowtie

iTrader: (6)

does anyone know roughly the compression ratio of some 5.3L heads on a ls1? i will not be running any fi so it will be n/a, should i mill the heads etc. or will the compression be high enough already? thanks for the help....

Out1aw

iTrader: (1)

9.5:1

53bowtie

iTrader: (6)

i thought an ls1 stock is 10.1:1....does the 5.3L heads not make this higher? i thought that is why all the camaro guys put them on their ls1 to raise their compression?

Out1aw

iTrader: (1)

I'm sorry. I thought you were asking for a 5.3L motor compression. Didn't read the whole post thoroughly enough.

It will raise the compression ration to ~10.5-10.9:1 that I have seen, all depends on whether the heads have been worked or not.

And just an FYI, a set of milled LS6 heads will be right at the same CR as the 5.3's.

53bowtie

iTrader: (6)

will the ls6 heads flow better? i am thinking of porting the 5.3's and having them milled .010....but if its 10.9:1 maybe i shouldnt mill them....i still want it to be streetable and on pump gas....