I got a nice 9" that is brand new from a buddy that was setup for a Falcon. There are no Drums or backing plates that came with it, just axles and some steel wheels with approx 4.5" backspacing. I measure 46" between the tires. and looks like axle flange to axle flange is about 54". My 30' coupe subframe without sheet metal is roughly a hair under 43". Not running fenders. That gives about 1.5" of clearance on each side. Is that enough? Might be too tight?
Yeah most of the wheels Im looking at had a 4.5" backspace. The OE chrome reverse wheels that I was looking at in a 15x8 didn't really have any 3-in backspacing. At least that I saw I might be wrong? Or even 3.5" would help.
To gain about 3/8 inch you could install extra long wheel studs,and run a wheel spacer.Its going to be tight.
Yeah most other rears I've read were 55" min wheel mating surface to wheal mating surface or 57.25". So im 1" shy of 55".
It might be doable, it’s gonna be close. 54” seems a bit narrow for a Falcon I had a 9” built for a ‘65 Falcon I built that was narrower than stock I think it was 54 1/2 if I recall. I use a lot of the wheel vintiques OE wheels They are 3.5-4.5 for most standard 5”-7” wide wheels. I’m very tight like that on my ‘40 I get an occasional rub on the inside from body roll but I’ve put many many miles on mine like that you might try it. Worst case you may need custom offset wheels.
I would think 1.5" inches of clearance should be plenty. I'd try it and then add a spacer if it rubs, but I think it should be fine. Of course if you have a very expensive paint job on your car, then you need to be sure.
Just a thought if your not too far along in the build.....move the inner wheel well of the quarter panel in at the top.A mini tub if you will.An inch ,or so per side at the top. It would barely show.
Since they are steel wheels, you can also change the backspacing by removing the centers and welding them in at a different backspacing.