My retro-cruiser (56 Customline Vicky) needs some oomph! I want to swap out the original 3 spd -no o/d for a good 4 spd with minimal hassle. What should I look for in the 'yards' that will bolt on if possible. I have a 57 9inch (3.10) already in but just for the street, would prefer a good 4 spd. for cruizin'.