Originally Posted by transamsam98
the ls1 in our fbodys had 2 different heads if im not mistaken. but alot of guys are using ls2 or ls6 heads among others with minor adapting. the benifits I am not 100% what heads change what with porting.
3 different castings, 241 (best flowing and came on mid year model 2000 and up) 853 same design as 241's but were sand casted, and not die casted so didnt flow quite as well, and there were the center bolt heads (previous two were perimeter bolt heads but i cant remember the casting number. as for the other heads, some flow better, others lower compression (6.0, good for FI), others are good for higher compression (5.3, and more power NA) i know its kinda vague, but i hope that helps