63 Dodge Dart, now let me see;)
You may get to it before I do on my Barracuda, so when you get to the mock up point with the motor and transmission sitting where the will reside....check the top transmission to bellhousing bolt on the passenger side. Seems like I remember them being really close to the floor pan. Back in my late teens or early 20's, I bought a 65 Barracuda Commando 4 speed car. Someone had cut a hole in the floor pan above that bolt, with a hole saw, and had a round plastic plug in it. You could pop the plug and get a box end wrench on that bolt much easier than wrestling it from below. It may be something worth doing to prevent future cuss fits...lol. I'm sure gonna eyeball it on my Barracuda.