A500

Early 90s Dakotas
TrailBeast did this swap. He has a thread on it.Others also have done it, you don't have to be a trailblazer anymore.
Crossmembers are now being produced for 67 up cars
Some cutting is still required, plus a bit of custom fabrication.
To install one in an early A is gonna get ugly.

IMO these are great for a small engine car. You can run 3.91s to 4.30s, to get a fabulous starter gear, blast thru the gears, and still cruise in comfort.
A teener with a small cam, like a 262 is a good example.You could stuff the rear with 4.30s for a starter gear of 11.78, with which the teener will rocket off the line with, no need for a really big TC. It will burn thru the gears hitting 34 at 5000rpm, at the top of first,and will hit 61mph at the top of second, 94 at the top of direct, yet cruise at 65= 2250rpm! Nothing wrong with that! And the 262 cam will pull some really good mpgs with a 2200TC,ie stock 340 convertor. That's a win,win,win. Buy tires. Lots of tires.lol
With a big engine, or a big cam, there is less of a payback.These don't need a big starter gear, and cannot properly use the overdrive, with a smaller starter gear. I think a mild 360 could still use it, but with those 4.10s the cruise rpm of 2250 is not so good for cams bigger than about 270 advertised.It's still a great combo, It just makes a little more sense with a 270 or smaller cam.And yes, the 360 with the 11.78 starter gear and 270 cam will be a tire-fryer, invest in some traction aider, if you don't want to be buying tires every spring,lol.

I often think that a streeter just needs 3 gears; two closely spaced ones to hit 60 with, and then a third one, waaaaay over there to cruise with. Then you just put a matching rear in it to hit that 60 at your engines redline.
Ima thinking the ratios should be around; 3.40-2.27-1.00 and the rear end should be a 3.23. This will get you roadgears of 10.98, 7.33 and 3.23.Your mph at 5500 plus slip, would be 40,60,and 137lol, and cruising would be 60=2400. What more could a streeter want? 2 gears to 60, and cruising in comfort. Other combinations are,of course, possible, but you get the idea.This direct third gear would make overdrive unnecessary.
Everything should be made to fit into the 904 sized box.
Joe Average-Streeter could save thousands of dollars. Ok hundreds and hundreds,lol.Yeah that would be something.
If it was affordable, I would be first in line for something like that.
To get that 10.98 first gear with the current 904/999 options,you would need a rear gear of either 4.00s or 4.48s
To get that 7.33 second, you would need a rear of 4.77s or 5.07s.
I mean think about how often you use third in your automatic tranny, and what you use it for. Mostly it is just a cruiser gear, to be used after the revs get too buzzed up in second, right?
With the almost perennial favorite rear gear,the 3.55s; "too buzzed up" is about 50mph @ 3200. At that point do you care what the rpm drops too? Hardly. You just slam it into drive and mosey along. If it dropped to 1826 instead of 2205 would you care? Probably not. Would it be worth the fabulous zero to 60 sprint to run 3.23s in third?
To me it sure would.
I would take a 2+1 anytime over an A500.
But I'm dreaming, aren't I,lol. Like that's ever gonna happen.....