something just started knocking in my 5.3 last night, sounds like it's coming from the bottom end. i'm looking at a lq9 shortblock, if i put my 862 heads on it what would my CR be? i'll most likely get bigger valves and maybe port them some. i'm on a very tight budget i just graduated college and haven't had a job in a year so i'm pretty broke. i dont really want to go buy more heads unless my CR will be too high. how much of a power loss will the 862 heads be compared to the 317s

 

You would get a bump in comp but they will not be able to breath aswell, due to the small chamber(61cc)vs 317(71cc) and the port volumes(intake 200) exh 70) 317 (intake 210 exh 75)...

 

find you some 243 heads, 64cc chambers and around 10.9:1 cr like an ls2

 

An LS2 is 10.9:1 compression?!!

 

243s on an LQ9 goes up a little above 11:1, not identical to an LS2.

 

yeap nice huh
well...close. 10.9....11.1. everything is the same internal, except maybe the piston dome. are the ls2 pistons dished a bit?