A855 - 5 Speed
For the record, I also looked into the tremec 5 and 6 speed.
Spoke to a number of companies that sell kits.
The 6 speed was out, too big, I didn't want to modify the floor pan to that degree, and couldn't with the bench.
The 5 speed was out as well. Not as much modification to the floor, but I got measurements from a few companies, and the shifter ended up extremely close to my bench seat. It would fit, but the boot would be under the seat, and I wasn't convinced the bench would fit back in, or it would go into gear against the seat, even though the throw is much shorter.
Plus it moved the shifter over to the right, centered, and I didn't like that.
For both, I also didn't have the funds to start that project, even if I sourced a trans from somewhere else, or used.