I am doing the design work myself and since I would like to sell some one day I have to be able to make some molds form the car. It is easy to do a “one off” but hard to make sure you can pull a mold from it.
I have a Chey 383 (350 with 400 crank) mated to a Audi 5000s transmission (This tran is shorter than a Porsche which worked better with the longer motor).