can someone point to a diagram of how the rear AC bracket installs? I have 2 different brackets that were loose in the car, no idea which one is right or how it fits.

 

ok, i figured out which bracket was right, it is marked 391366 D2. the other one appears to be for a 66 Toronado.
the bracket attaches at 2 points on the engine: a head bolt and a blind hole in the intake manifold. I have no hardware to attach it, so need to figure out what nut size fits the head bolt stud and what bolt goes in the hole in the intake. it appears to be fine thread.
the threads are also in poor shape in the intake and head bolt, so that makes it a little harder.

 

in case anybody cares, the threaded hole in the intake for the AC bracket appears to be 3/8"x24. a tap that size went in without much resistance. threads were pretty bad, i guess bolt wasn't in there for a long time.
also, the nut that threads on the head bolt stud is 7/16"x20.

i figured this out by just buying some nuts/bolts at home depot and seeing what worked. not well versed with standard size fasteners.

 

looks like the aftermarket edlebrock valve covers don't clear the ac bracket.
back to square one

 

6 hours of work later, I made a rear bracket. looks like crap but works.

 

charged up and it's blowing cold air. the stock GM stuff doesn't seem to mind the 134A.
i think the bracket could use a gusset though. i'll see how it holds up.

 

You must be thinking out loud or talking to yourself, the rest of us are quietly listening and being polite.

 

I'll agree it's not the most elegant bracket, but it works ands that's what you need first, you can work on looks on rev2

I made a couple brackets on my engine too, one is like yours in that it's obvious it's a part not from the factory, the second one tho I welded and ground to look like stamped piece and IMO it came out great.