I have what I believe is an original LS6 car. Everything matches the build sheet, but not the tired motor. Vin# 136370B152080. Replacing the existing 454 '78 truck motor with an original LS6 is expensive and not streetable. Should I consider a "crate 454" or rebuild the existing motor? It's a nice driver, restored and looks great, but no 100 pt. car. I want to drive it, not show it. Any advice?

I would first check out price differences
It might be worth it to rebuild your existing motor. You could build it any way you wanted. But the money you spend rebuilding your's could also be the same as a GM crate motor with a factory warrantee.
Just a thought.

Jeff.

It is my opinion that i could rebuild any long block to pretty much any specs that i want and spend less money than an equal crate motor would cost.

consider the magnaflux job, the balancing, and the machinists skill & experience your warranty http://www.chevelles.com/forum/smile.gif

however, i think you should take into consideration how much you could sell the old "core" for, etc..

mike