Please watch the dates on posts you reply to a doubt the original poster still has the car 6 years later, He has not even logged on to the site since 2/17/2015.

GM stopped putting the LT1 in 4th gens in 1997. Installing one would be a huge waste of time and money. With these swaps you really need a wrecked doner car because everything from the v6 to the v8 is so different. IF you had to swap a 99 v6 to a v8 the beast way to do it would be to find a wrecked LS1 car. This is well documented the the V6 tech section and if you research it in the project section you will find it covered many times. You can pc meal a V8 swap together and there is a thread were a very knowledgeable guy swaps in a LS 5.3 out of a truck. By the time he is done with parts and customer wiring harnesses he is in 5-6K deep without any labor cost. and he had the motor already.