I have a 1974 Kombi and have an original motor that came with it. There is a serious crack along the engine block which causes it to leak oil. I have decided to sell the motor for what ever I can get for it and go with a new or used motor. I have heard about Volkswagen selling 1.6 and 2 L engines for the Kombi and have also heard about people using 3 L Porsche motors. What motors can I use without making serious modifications to the engine bay or transmission?