With an LS1 Fbody the focus should first be the induction and the exhuast. The Fbody has a funky stock air indution setup with huge baffles that are supposed to silence the incoming air to meet EPA noise regs. I replaced mine with a standard type cold air direct flow lid and noticed no differnce in sound. That leads me to belive that the real function of the stock baffles is to limit Fbody HP to less than that of the Ls1 powered Vettes. The exhaust manifolds of the Ls1 Fbody are much more restrictive than the Ls1 Corvettes as well. Headers of some type are a must. There are a ton of Ls1 cars with headers, MAF ends, lids and Catbacks running around with 315-330 HP at the rear tires. On a car that was built 97-2000 an Ls6 style intake is agood upgrade that is worth 10 HP on average to the rear tires and it allows for much better gains with a cam swap. The stock Ls1 cam is tiny and the stock heads will support much more power than the stocker is capable of making. The stock cam is like a 198/202 with .499 lift on a 116 LSA. Most people go wtih a cam that is at least 215/215 with .530 lift or more on a 114 or 112 LSA. The most poplular cam onl swap for the Ls1 is a 224/224 .570 lift or better cam.