check these out from YearOne if you do end up needing some extra room. I've got a set that came with my car I haven't installed yet but they seem to be great quality. 1966-74 A B E-Body Universal Seat Relocation Brackets
Thanks for this. I got these and installed them tonight. You wouldn't think 1 1/2" would make that much difference, but it sure does. If any of the rest of yall want to get these, get through Amazon like I did. Free shippin and the same price as Year One. They even came from Year One, but they wanted 15 bucks shippin.