Hi Andy, I believe that the SB Model 33 (first introduced 1953) had metal clutch housings...I am not sure about the first model Scotty 45's....I am lead to believe that they were alloy....
BTW. There has been discussion of late where the clutch assembly has been thought of as a flywheel....this is, of course, incorrect....the flywheel is on the other end of the engine (also supplying the electrics) wink
cheers2

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin