I am new to this forum and to older bikes. I have a cbr f4 but its almost to fast for the crappy roads i live near so i plan on tracking it. For a more cruiser style bike I am really interested in buying a 70s cb 550 or 750, I like the idea of the 750 because i would eventually like to do a big bore kit up to 836cc. There is a 550 for sale down the street and I was wondering if a 750 engine would fit into a 550 frame. It doesnt matter if the mounts line up I just want to know if it will fit.