I have a 77 sprint veloce that needs a new set of crank cases. I thought I'd tune it slightly and have ordered at set of LML150 ( reed valve 3 ports). I haven't received them yet, but on reading up I've discovered that the early p range 150's had a slightly smaller end on the input shaft than the later (LML) . My question is will a later post 83 input shaft fit a 1977-8 christmas tree cluster. Is it just the shaft that is different, or is the tree also a different size.

Obviously if I need to change the whole christmas tree, the rest of the gearbox will need replacing...