I was building a bunch of 4.3's V/6'S around five years ago but I quit building them when I found the LS1 was much lighter and more powerful. Plus when you make 350 to 400 HP from a V/6 your pushing the reliability a bit to the edge. They are cool little motors but a LS1 is lighter, more powerful and more reliable. The only reason to run a 4.3 over a LS1 is if you had one lying around.