Pretty much.

 

a higher-compression 5.3 at that

 

No. Piston pin height is different. Ive been out of the game for a while, and been a couple of years longer since I was dealing with a 5.3 Never had much experience with the 4.8 at all, but its possible the rods are different lengths.

IIRC, the pistons are pressed on in the 4.8, and the 5.3, so best bet would be to get crank, pistons, and rods. I know for sure you have to have the crank and pistons.

 

haha thought so.. after i started thinkin about it i thought back to my 408 i built for my camaro and remembered when i went to the 4 inch stroke i went to a 6.125 rod and diff piston... but i didnt know if the rods/pistons were diff on the 4.8 or not..

 

for a 4.8 i think u jus gotta swap the crank and rods to make it a 5.3.. the flat top pistons will up the compression which isnt a bad thing?? unless its to much