Wow, 17 year old kid building an SBC and hot rodding an e30. While I don't share your zeal for the project (BMWs should be all BMW) I do respect your ambition. What mods did you do to the engine? Hyperutechtic pistons, flat top? PM rods shot peened for strength? Running a hydraulic roller cam, electric water pump, 1:6 ratio roller rockers? You gonna juice it too? maybe a dry injection system? Bottom line, you're in for a HEAP of work and broken stuff to get it all to work. It can work, there's a guy at my school right now with an e36 and an ls1 in it, took him a while and a hell of a lot of electrical "fiddling" to make it reliable. I believe he is running the stock rear end and he hasn't detonated it so maybe you will get it to work. But as pointed out earlier, you destroy the weight balance of the car, change the suspension dynamics, your power steering gets tricky and wears out quickly because of the weight difference. But like all hot rods, it'll go like stink in a straight line, just depends on what you plan to do with it. Good Luck