Ok I am looking to do an ls1 into my 91 silverado. I would prefer a 6.0 but would settle for a 5.7 or a 5.3 honestly. Anything will be a big improvement over my TBI 350! I look around ebay alot trying to find out exactly what I want to do and from reading on this board I am even more confused. I apparently need to do more research on the 6.0l's to find out the differences, which model 6.0 should I try to pick up for my truck? Same thing for the 5.3's. I definitely know the differences in the 5.7 ls1's but the others I am not up to par on.