Just got a pair of 2006 243's off a 5.3 h.o. .My question was are the valves longer like they are for the ls6 or are they standard length. My second question is how much should I resurface the heads to use them on a 4.8/5.3 non h.o. without losing compression and to gain compression say 10:1 or 10:5.1
thanks Chris

 

I read here somewhere that "sportside" had some milled and didn't really see any gains??? I don't know I just want opinions.

 

I don't think you can mill enough to ger the CR you want w/o pistons. Your best bet is to sell those and get a set with smaller CC combustion chambers ported and polished.

 

.035 mill should get you close

 

POPO1984 is right......

Or you could go with a thinner .040 gasket which then you would only have to mill about .015-.020.

 

or both, just watch piston to valve clearence