Just tried this 2 weeks ago. I have a 71 road runner and a 71 cuda. I'm having the cuda seats re upholstered and thought i could put my road runner seats in the cuda to move it around the shop. Turns out the bolts to the floor pan are at least 1/4 inch further apart in spacing on the road runner. I'm sure I could open the holes but didn't want to pull the carpet. However the seat tracks from the cuda bolt directly to the runner seats and allows me to bolt in a seat to move the car.
I did it twice and don't think i had any problems. It's been a while and I've worked on a gazillion cars but I don't remember having to drill or anything. The holes are fairly larger than the studs. I might try it again. I have a bare 72 RR shell and a few sets of E body tracks down at the yard.