Would installing 4.8L heads on a 5.3L up the compression ratio thus giving more power. What hp gains could be seen from this? Would it hurt the internals overtime(increase wear)? Would there need to be computer tuning or would a HPP3 work? Would you be able to tell the difference in perf in doing this mod? Just wondering Would this be an easy swap (just pull off the 5.3L heads and bolt the 4.8L in their place)? Is it hard to take out engine heads off? May be interested in this mod since my parents bitched at me because I was going to put a cam in my truck, hopefully this could be a mod that I could go to my freinds house and pull it off in a few hrs without them knowing. Need all the info Thanks

 

Same bore, same heads, I believe.

 

Matches everything I've heard ....

 

The 4.8 has a shorter stroke than a 5.3. Thats all. Just take your heads to a good machine shop and have them mill them. It usually only runs @ $50 per head for a basic mill job. Porting is a couple hundred more though. Also if you mill your heads much be sure you have the right length push rods.