I have a Viper T56 in my 68 dart. I used a transdapt crossmember bolted between the frame connectors. The tranny mount and the shifter are further back on the viper t56, but it still fits with my bench seat. For the torsion bar crossmember, I made a new one using bent tubes cut in half and welded new sheet metal over it for the floor. The stock auto carpet fits like a glove and you can't even tell the tunnel has been modified.
6 speed is so much fun to drive, worth every penny to do the swap
