SJW, my car was a long-abandoned airplane hangar find and that's the trans that was in it. I may at a later date install an ST-10 or Muncie with a 2.52-2.66 low gear. As it is right now, my SECOND gear, at 2.20, is the same as FIRST gear in a close ratio Muncie M-21.
I would say dimensionally you should be just fine. Mine is a '61, but no modifications have been made to the floor or shifter porch to accommodate the ST-10 and Hurst shifter. My shifter runs right through the stock shifter plate bolted to the floor, using a Hurst adaptor to mount the shifter to the trans. If you want to go with a Muncie 4 speed, Tom Parsons has all the info. Pretty much a bolt-in with a couple of cross-member spacers. The old T-10 is weaker than a Muncie or an ST-10 trans, so either will be an upgrade to your car. Here's mine, with an early '60's Hurst 9" curved shifter on the ST-10.
