Newbie here - 1st generation Barracuda
First off, welcome to FABO.
First would $1250 be reasonable for an engine-less body in fair shape?
Not a bad price, if it's clean. I gave $1800 for mine as a rolling chassis V8, 4-speed car, aluminum slots with brand new tires and some other parts that I was able to sell to get the price back down; however, it was extremely clean back then. That was before I parked it outside over grass for a year. These models don't demand a lot of money, but I have a soft spot for them.
What to watch out for? I assume the US A-bodies are prone to rust in similar places to the Aussies? (quarter panels, floors, spare wheel well, bottom of doors) What about other places?
Those are the typical rust areas.
Engines? I think the first gen Barracudas came with a 225 Slant 6(?) but I assume it's no trouble to drop any of the early LA motors into it?
Some came with 273ci V8. The throttle assemblies are different between the /6 and V8 versions.
Trannies? Back in Australia years ago, it was fairly common and easy to mount up a 5 speed floor shift (Celica boxes were the most common). Does anyone make hardware to do something similar over here?
You have many transmission options: 904 and 727 automatics, 3-speeds, 833 4-speeds (ball and trunion or later model), numerous 5-speed options, and even T-56 6-speeds depending on what parts you have available and how much you want to spend.
Brakes? There's gotta be options for disc brakes? What about other handling improvements?
You have many options for disk brakes as well: KH disk brakes, 73 and later single piston disk brakes, and numerous aftermarket options. I went with the 73 and later single piston version as there are many donor cars out there.
Parts/sheet metal in general? There was a decent aftermarket for replacement parts for the old Vals in Australia when I left there - you could get new sections for the rust prone areas and you could still get rubber stuff like engine mounts and spring bushes, and some electrical new from the dealer. How hard to get parts over here?
Not bad, there are a few companies still making parts for them. Plus, you are on the best site for people sharing information on building these vehicles.
Once again, welcome to FABO.