['ol Pinion head]

Will take as shot at this since noone has answered & know the buckets fairly well. The horsecollar type A-G body bucket seats & the regular flat top '73+ Abody buckets will have the seat tracks you need... won't need to hunt down & swap seat tracks. 2nd Gen Firebirds & Camaro's used lower profile seat tracks & there are actually several different versions. The '73-77 A-G body horsecollar seats were also different from the deluxe Firebird seats in the design of the seat back release (look at outboard latch area). The large plastic seatbacks are also different as the F & X body versions have the notchs to aid in accessing the seat release. Having pulled a ton of these seats, I'd be on the hunt for a decent pair out of GrandAm, Lux Lemans or GP, they'll have the tracks you need, & all together ought to be easier to find & considerably cheaper than same year (nice shape) Firebird horsecollars.

As far as inner seat track mtg goes, going to have to hand that off to someone who has replaced floor pans in this era of bench seat A-body. I've processed & cut floorpans out of several '73's & '74's, but all have been factory bucket seat cars.

[75cancup]

If you find a donor car you will need the factory seat brace that goes from side to side , it is spot welded so you will need a good 3/8" drill bit and basic prying tools to remove it . You will also need the one small square plate that has the seat mounting bolt on it .
Take a note pad and take down all the measurements . Clean it all up and remig it to your car.

I have removed these braces too keep them for others doing this but i don't have any right now or they would be yours . mike.
Check the 73/77 abody section maybe someone has a spare set for you.