Is there a book/web site that has interchangeable parts list between model years. Mostly sportster engine parts.

 

Not that I have come across! If you want answers to specific questions our experts in here can probably help, but otherwise that is an open question, with too many answers to easily set down - without writing a book.......

 

yes their is , I had one last year and lost it , it was some type of parts catalog and in the back it had a list of years for example
fenders
91-03
85-90 like that , my mechanic also has one

 

You can also just go to a Harley Dealer site with OEM microfiche (I use Ronnies HD), look up the parts on your current model, and then compare to the part numbers on subsequent.

If the part has been re-issued under a new part number, they will update it on the old fiche with an * to let you know its the same