Here is a site that will help with model and frame numbers.
re: putting a SOHC 750 into a DOHC 750 honda good luck there as everything will be a pain in the ass.
http://www.hondachopper.com/SEE ENGINE SECTION
Also, try out these other good sites
https://www.partsnmore.com/http://www.oldmanhonda.com/http://www.homemadehonda.com/Good Luck
Chris