I just picked up a GT80. 393-206xxx. I think that makes it a 1974 GT80B. I would post a picture, but you don’t want see it yet. Pretty rough. I need to round up some misc parts. Should I invest in the parts manual or is the CMS website reliable for part numbers? I’m used to old Harley’s where you have to have the parts and the factory service manuals to get the full picture. 

 Both are useful . Online lists usually show the latest superceded part numbers .
That's good if you're ordering from a dealer . They don't always show the original numbers ,
and if you're sourcing NOS parts off Ebay , you'll need those .
The parts books are a great reference for checking Ebay listed numbers , as sellers
have been known to list them incorrectly . I have a box of parts I bought without double checking
the numbers were correct for the model I was working on . It teaches you to do your homework .

Thanks Swoop. Im rounding up the odds and ends. My 8 year old helped me pull the primary cover off to pull the kicker shaft off. Once that part comes in we will see if it’s starts.