I have a titled 75 xlh ironhead and it is the original right side shift, no cross-over. My concerns is my transmission, I have been told that something like parts are basically interchangeable from 71-76. I bought a complete transmission from a 73 xlh, casting numbers 34845 54A, the one in mine is 34846 54A, will the 73 fit right into mine or do I need to change something? Also my engines code *3A29292H5