Welcome to the Stovebolt wave

That seems like a lot of work for no gain of any kind other than floor space, both transmissions are direct drive with 1:1 high gear ratio. The SM-420 is bullet proof behind a 6-cylinder and you'd drive it like a 3-speed, starting off in 2nd gear all the time.

Mike B smile

Mike Boteler

1956 Chevy 3100 Resto Rod
1952 Willys M38 Army Jeep
1983 Jeep CJ7 Laredo
1984 Jeep CJ7
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Silver Spring, MD