This is ProCharger stuff does not make any sense.

Im in the market for a ATI LS1 system. They state that the 4# system has an FMU and fuel pump, and the 5# & 7# system does not. Now, why would they not include it in their better system? Can someone help me pick out a system? This would be going on a 2000 SS with 3K miles. 4, 5, or 7 # systems? What else would I need. Help!

get in touch with lonnie pavits, or tbyrne they will help you out for sure. good luck

The 5 & 7# kits are "tuner kits" that require aftermarket programming & injectors. The 4# kit is for stock injectors & programming hence the need for the FMU to control fuel. Hope this helps.

Thanks guys. Lonnie, heard good stuff about your service. So, if I was to purchase the 4# kit, I would not need anything else correct?

What if I was to purchase the 5 or 7# kit? What size injectors would I need? What kind of programming? Thanks guys.

if you're like the rest of us, eventually 4#'s won't be enough, I'd do the tuner kit and spring for the dough for injectors/tuning. Think of it this way, a 2000 tahoe that I was running 9#'s and getting 13.9's wasn't enough. Now I have a new engine going in with a F1......of course everyone asks me why did I go so nuts with my truck rather than either of my camaros, and my only answer is....did you see the face of the guy in the mustang when I beat him with a 5400 lb truck? If it were my car I'd go with the 7#'s.