Buy the Corvette model if you just have to get an LT1. I wish I could talk you out of it and into and GenIII engine. Yes, the 5 speed will work behind the LT1. I ran my factory V6 for 120,000 miles(rebuilt twice) when I ran the LT1 Corvette engine in my truck. You are going to have to modify everything to do an LT1 conversion just like you would have to do a GenIII conversion. Fuel pump, motor mounts if you have a V6, wiring harness, exhaust system(unless you already have a V8, reuse the stock manifolds or headers), fuel lines, electric radiator fan, fan shroud,....