So i was just lookin on the internet tryin for find the most powerful 4.8 out there but i stumbled over something. i was lookin on wikipedia and it said the bore on a 4.8 an a 5.3 is the same. but the 5.3 had a longer stroke. so dose this mean all you have to do to get a 5.3 it put a crank an some rods in it? here the link. http://en.wikipedia.org/wiki/GM_LS_engine