It might be necessary to open up the hole in the bellhousing. A machine shop with a BIG lathe should be able to do that, but the setup time to get the hole dial-indicated concentric will probably cost as much or more than the actual time spent reboring the hole. A SM-420 would probably be a bolt-I'm swap.

OOPS! scratch the above advice- - - -the 1940 has a different bolt pattern for the transmission and a different motor mount setup. To use a 57 truck bellhousing you'll need to install a 54-up crossmember under the bellhousing, do the above hole enlargement, AND fabricate a bracket to support the pedal mount.
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!