54 Chev SM 420 Swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RainierMan · 08-04-2017, 09:28 PM

I have a stock 54 chev 3100 truck with an SM 420 trans serial number 591465 which puts it in the 47-53 range. See pic in truck. I bought an SM420 serial number 3830574 which puts it in the 64-67 range. It has a 10spline output. see pics. I want to know if i can convert the newer one to fit up with the torque tube u-joints on the old trans or do I need one of the correct vintage. It appears its doable. Any help would be appreciated.

RainierMan

08-04-2017, 09:28 PM	#1
RainierMan Registered User Join Date: Aug 2017 Location: Ashford, Wa Posts: 2	54 Chev SM 420 Swap I have a stock 54 chev 3100 truck with an SM 420 trans serial number 591465 which puts it in the 47-53 range. See pic in truck. I bought an SM420 serial number 3830574 which puts it in the 64-67 range. It has a 10spline output. see pics. I want to know if i can convert the newer one to fit up with the torque tube u-joints on the old trans or do I need one of the correct vintage. It appears its doable. Any help would be appreciated. RainierMan Attached Images



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