I would say the floor pan got welded in a bit off when it got replaced
if it were me I would make sure the crossmember is centered on the frame
and if it is ,,, it looks like the hump needs to come back of and be modified ...
you do have the early porch with the round hole as our 68 n ups had a larger square hole ..
Okay... so I did a little bit more digging, and I think I may have a lead on what is going on here, I just want to see if there is anything else I might be missing.
So I got back under the car tonight after working on the suspension as to alleviate my frustration with this issue. But with that done back to the shifter. there are a few things to note.
1. When I was adjusting my shift linkages I had to screw the adjusting nuts out quite a bit to be able to get them in the correct position. so much so that my 3/4 linkage actually slipped out because it was adjusted out so far.
2. Just for Shi** and giggles I took the mounting bracket off all together and bolted the shifter directly to the tranny. Doing this seemed to make the handle line up almost perfectly in the hole of the hump.
3. I started looking at the mounting bracket now. Based off what I found online, I have a 67-68 mounting bracket with my 66 shifter and linkage. Looking at pictures of a 64-66 bracket online, I can see that it mounts a little closer to the front of the car. so this would fix my linkage adjustment, but wont help with the offset in the hole for the shifter.
4. The transmission is definitely centered in the middle of the frame
So, next I will definitely source a 66 bracket, but my next question is does anyone know if the 64-66 mounting bracket is thinner than the 67? will this help with my offset. Also... would it be a terrible idea to mill down the bracket a 1/4 of an inch to help move the shifter body further right? I'm open to any suggestions.