I have a set of stock assembled 243's. LS6 heads. Brand new. Never been ran. Valves still have paint on them. Stock springs, not the yellow ones. Not the sodium valves. I bought these for my 6.0 build but am now going a different route.

450 shipped.

 

I would want to put these on a 5.3. Can they be milled enough to get a 10:1 CR, or would it be a good idea to get a different set of heads?

 

yes can be milled. As much to put you to P to V problems i would assume?

 

bumpity.