So I have an SM420 (88373340, but the first '8' appears upside down) that I think is from a 1965 GM 1-ton plumber's truck.
I my open drive-line 1939 Chevy JD truck has a 1957 235 engine with what I think was the original 1939 non-synchronized four-speed transmission.
What is the best path forward to get this transmission behind my engine? Just eye-balling it, it doesn't appear that the bolt pattern of the bell housing matches the SM420. Is there a specific year or P/N of the bell housing that I'm searching for? I'll add this to my wish list when I go to the Pomona swap meet.
--BeeMAC1975
Last edited by Peggy M; 12/13/20233:16 AM. Reason: added more info to the title with the move.
I think Pre-68 Dave has a blog on his website that details the process of fitting a later transmission into a pre-war or Deco truck. I’ll go look later unless someone beats me to it.
A 1948-53 truck bell housing should mate the engine and trans together, but you might have to do a little tweaking to make the pedals work, and possibly do a little custom fabrication on the motor mounts. The 54-up bellhousing will also marry up the engine and trans, but motor mount modificatiopns and possibly a firewall area crossmember swap would be needed. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I am in the process of doing a similar conversion. I am installing a 62 235 with an open drive shaft SM420 in my 1939 JD (3/4 ton). I am using a 49-53 bell housing. I will need to fabricate a bracket to attach the pedal assembly. Instructions for bracket are for big bolts and somewhere on this site. Don't remember where but I have copy of the bracket plans. attached are photos of progress to date with casting # of bellhousing.
