I have an 84 hurst olds, and I recently purchased an ls3 out of a 2012 corvette to drop in it. It came with l690e transmission out of a silverado. This monster transmission isn't about to fit into the tunnel, and I really don't want to cut up the car. I've heard an engine like this putting out 430hp will eat most other tranny's for breakfast.
I don't know enough about this...are there any other smaller transmissions that will fit that can be rebuilt/beefed up enough to handle the power??
the corvette unit is designed to be at the rear with a torque tube couple options build your 200r4 there strong units built correctly or a 4l60e can be made to handle it and easy to swap or a 6l80 from a camaro or 2wd truck
A well built 4L60E from one of the sponsors (Performabuilt, FLT, RPM, Jake's Performance) can handle 500HP with no problem. A stock one will not handle it for long. If your budge allows $2000-$2500 you have many choices.
If you plan on a adder (turbo, supercharger, Nitrous) which would boost you well past 600HP, you may want to consider a 4L80E.
If your budget is tight, you might consider a TH400 as even a cheap stock rebuild will easily handle 500+HP. Just no overdrive.