Yes it is part of the family but not an ls1. The point is people throw around the name like it is going out of style. I don't know if it makes them feel better to say they have an ls1 or what but there is only 1 all aluminum 5.7 engine and thats the ls1. Dont take it as a hit on you just thought people should know that just because they have a 4.8 or 5.3 doesn't mean they have an ls1. Interchangable parts-yes, but still a different animal.