I have a friend that picked up a “1947 U motor and transmission, completely rebuilt, zero miles". He is looking for a frame to put it in, and wanted to know if there is a difference between a UL frame and a Knuckle or Pan frame? Will the motor mount in either? Will it mount in a later duo-glide frame? He wants to make it a runner, and look old but does not want to get all the parts and or money together to build a stock bike.