If they are using a 40's chevy engine...it should be the same...at least interchangable thru the '50's... there's lots of parts available for Stovebolt engines still.
Does it have a reversing gearbox of some sort?
I used to run a Brill interurban car that had a Fairmont gearbox that gave us three speeds in either direction, with a chevy big block V8 and turbo 400 trans...its biggest issue was the gearbox and the way it was mounted, causing regular breakdowns...