i only have a handful of motor numbers/brands. there is documentation for this, but i can't find it. i thought that info would be in Tecumseh parts manual, but if it is, i can't find it. markus i think has a list but he's seems to keep that close to his chest. all i have is this, which is from bikes i own or have seen (somewhere). i try and keep track of it, but it's hard to find bikes with original motors...
Tecumseh H50 65151h - 1969 Roadster (with lighting coil)
Tecumseh H35 45303g - 1970 Sprint, gray
Tecumseh H35 45304g - 1970 Scrambler, gray
Tecumseh HS40 55295c - 1970 Fox, gray, diaphragm carb (non-angled intake)
Tecumseh HS40 55282b - 1970 Roadster lighted version, gray, diaphragm carb (non-angled intake)
Tecumseh HS40 55330c - 1971 Black Widow, Dellorto carb, long governor arm removed.
Tecumseh HS40 55331c - 1970 Roadster lighted version, gray, diaphragm carb (non-angled intake)
Tecumseh HS40 55355c - 1971 Hustler, with angled intake. Also this engine number seen on Black Widows with Dellorto carb and long governor arm removed.
Tecumseh HS40 55356c - 1971 Roadster2 lighted version, black, with angled intake
Tecumseh HS40 55388c - 1972 Roadster lighted version (date code #1337c, #2032b, #2070c)
Here's a couple that i can *not* confirm, but i have written down....
Tecumseh HS40 55354c - 1971 Roaster2 lighted version, black, with angled intake. The 54c is a standard length bushing shafted engine????
Tecumseh HS40 55357c - 1970 Roadster lighted version with diaphrapm carb (non-angled intake). The 57c is a non lighted extended bushing shaft off an MTD????