you can also get 243s on a ls4, and ls2 thats why i was being a smart ****. the true ls6 heads have lighter valves

also that post is from over 2 yrs a go, since then they have made other motors with those heads.

 

Well I have the 5.3 heads already, so the 241, or 243's arent gonna be more cost efficient. I may just slap them on then actually work the 317's

 

With 61cc 5.3 heads and a .040 head gasket it is about 10.85:1
Mill the heads .010 to 59cc and .040 gasket it's 11.12:1

At least I hope that's right since my heads are on the way...