Well i got another 6.0 block, and i have a set of 799's for sale, well that is depending if they would be a good combo on the 6.0, wiseco 11.1 flat tops are going in along with a decent lunati cam, havent decided on what size yet, thanks guys

 

799 heads are the same as 243 heads.

 

The differences are the valves. The 243s came with hollow intake and sodium filled exhaust. From what I read the 243 and 317s are identical except for the combustion chamber. I 799s I think are indentical except for valves, I did a good bit of research on this topic and if my memory serves me correctly that is right. 799 heads will become the new low buck performance option as they start popping up

 

but for a 6.0 wouldn't the issue lie in the fact that the 799 and 243 heads are made for small bores, ie <= 3.898", whereas the 317's are for large bores, 4.0" and up? Or is this a non-issue?

I'd just think if you put a small bore head on a large bore you'd end up shrouding the valves some and not get as good a flow outta them.

 

He can have them relief cut with a grinder to match his actual bore much better the standard heads.

 

only the ls6 243 heads had the different valves. the ls2 heads had regular valves. and fwiw some replacement ls2 engines had one of each head on either side. i would have to say they would be the same.