Well, an LS1 looks to weigh in at 460 lbs (bacomatic number) and i got 512lbs from another forum where he weighed his (2.3T) wet, running including T-5 trans at 521. So minus trans, that puts it in the 440 lbs range. So, counting my trans, intercooler, and rear assembly I will already be heavier than some here more than likely. Thats without a car around the running gear....... So much for lightweight, though, compared to a dealer bought car it will still be light.