i sold that truck and got an 04 ecsb that is stock but a tune and flows right now but im also lookin into a l33 with a t56 for a 240
and stevon my 05 silverado 2wd has an lm4 aluminum block and its the stock motor i no they didin come out with the l33 till 05 and they come out with the lm4 in 04 so anything above that prob had an option of each not shur tho