what are the differences between the 5.3, ls1/ls6 block besides the obvious bore from the 5.3 to the ls1/ls6? are the oil passages different, one stronger than the other? planning on doing a boosted forged 5.7 and want to buy a new block bc i got burned on my old build buying a used block. theres a slight price difference between the 5.3 and ls6 block so i was just curious if there are differences with the ls6 that its a must to get.

 

I have the LS6 1168 It has bay windows to equalize windage pressures. I think that's like loose underwear.
Ls1 does not. I read somewhere that the 5.3 bored to 3.9 makes the strongest aluminum block. I don't know much about 5.3 though.

 

If the l33 is better then the new ls1/ls6 block than i will deffinatly buy that! Any more info on these to prove this? Also where can i get a new l33 block?

 

I don't think the 5.3 block at 3.9xx bore is any stronger than the regular 5.7 block.

If you leave the bore stock sized then yes, which alot of people do when boosting for that very reason.