Hi Wesley,
Did you find out how you tell the difference? I am currently trying to find out. My haynes is only mentions the 3 bearing engine and I know that the 5 bearing came into being in 1980. Problem is I have a 1980 SWB 2 1/4, so with Solihull being what it is I'm not convinced that this means I have a 5 bearing engine. Engine number is 90291364. Cheers me dears.