I bought the wrong transmission for my 66.

Well I want to remove the OD trans because it needs work done to it and I don't care for the 309 1st gear with my slant. So I picked up the McCandless trans thinking it would be an almost bolt in, except for the bearing retainer and shift rods of course. Yes if I do install this, would mean more downtime, another driveshaft, although they could reuse the ends.
Heck, I wouldda thought the 3.09 low gear wouldda benefitted a slant 6. Are you saying it's too low?