Quote Originally Posted by gm327 View Post
4.8 /5.3 have the same bore

they should fit, just that 5.3's have a shorter rod,

+ you should gain compression and flow, due to ur 5.3 has deep dished and 4.8's have fla tops and 243's should help alot...
More flow from a flat top piston?

But anyway, if the pin bore is the same new 4.8-old 5.3 then you can have your old pistons pressed off and the new ones pressed on to your 5.3 rods. the press fit in the rod will keep the pin from hitting the cyl wall so you shouldn't need the spiral locks.

I don't know if you can put PM rods in a rod oven. maybe someone here will know.