243 heads on 5.3l

[riccotxtre]

Have a 2000 Yukon xl1500 slt 4wd 5.3l 706 heads bad friend gave me 243"s will these work ok what shall I do? Would I be better off swapping out 5.3 with a 6.0

 

[iamdub]

They'll work. You'll lose a little compression so the power will be down a little. You may not even notice. If it were me, I'd have them shaved .020"-.025", maybe .030". Shaving would ensure they're perfectly flat, would restore (or improve) the compression and it's cheap to do. If you got the heads for free, then you definitely don't have any reason to not shave them. I'm always for more cubes. But, if the 5.3 is solid otherwise, and you don't need the little extra power and/or don't wanna spend the money for the 6.0 swap, then fix the 5.3. You can do small easy things to the 5.3 to match or exceed the 6.0's power and maybe still come out cheaper, depending on the cost and condition of the 6.0 in question.