What do you mean by "$1,000+ for an aftermarket unit"? You can find reman Sandans in the $300-350 range. The reman A-4 's are about half that.
You'll never find an AC bracket for the 292 in this life time, unless you are a hell of a lot luckier than most of us.
You can find 250 brackets for the A-4, but you have to extend it up to reach the head, which you know is higher on the 292. You have to get a new lower hose that is longer with extra bends to get it behind the part of the bracket(s) that bolts to the front of the block below the cam gear cover. Another part of the bracket(s) goes to the pass side motor mount, which you also know is in a different location than on the 250.
It's a massive piece (or rather four pieces) of S*** that you will have to do a lot of modification to, in order for it to fit.
I can't recall what the pulleys came off of. The crank pulley and the double water pump pulley could have came off a 250 with AC or even one with an A.I.R. pump.
