Gear Vendor and 833

For my combo it works exceptionally well, but a 5speed manual would be close enough, as could a 4-speed auto with a loc-up and a bit of stall. At the time 2004, I just didn't have the cash for a Nash, a Richmond, or a Tremec, and I didn't want an auto. And I would not hear about FABO, for another ten years; Joined in 2014.

If you think about it, an auto with a loc-up and a bit of stall is actually a neat combo.
The TC has an internal torque multiplier that can run typically to 1.8 at zero mph. So say your A500 has ratios of 2.74-1.54-1.00-.69, and it stalls at ~2400. Say your small-cam hi-compression teener is pumping out 280ftlbs at 2400rpm/360@peak-torque. All rpms are gonna be "about" and using 27" tires.
And you are gonna run 3.73s as in a previous post. This makes 65=2100, a perfect jumping off point for 20plus mpgs. So then your starter gear will be 3.73x2.45=9.14. Therefore with a manual trans, you would be slamming down 280x9.14=2560 ftlbs into the rear axles. But........ with an auto, the TC at zero mph could jack this up to say 1.6x2560=4100ftlbs@2400. Of course this multiplier rapidly decays to somewhere around 1.10 to 1.05, which would throttle it back.... automatically.. to a theoretical 2700ftlbs@2400,or so,(but you won't ever be there during the run to 60mph! on account of the rpm/torque is climbing as the ratio is diminishing.)
Basically, you can think of the TC as effectively multiplying at WOT,your 3.73s to 3.91s.
But at loc-up, the 3.91s revert to 3.73s.
And the .69 OD reduces that to 2.57s.
And you never have to service the clutch forever more.
Very clever, IMHO.
Now, for a streeter, 30 mph or so, is where it's at, so following are three examples with 30mph equalized to about 4000 at the top of first gear.

With the A999;those 3.73s are gonna get you 30mph@4000rpm in 2.74 first gear.With the right cam, that will be dynomite on the Kickdown; and second gear will get you 65mph@4900 so, not ideal but pretty darn close. and 65@2100 cruising in .69od. So yes you could use more rear gear, but that will increase your Rs at 30 and pretty soon it won't be worth kicking it down.
Don't forget, on-road torque of ; 4100ftlbs @2400@0mph,diminishing as the car starts moving, but simultaneously increasing with rpm; to say, reach a peak-torque of 360ftlbs x 2.74x3.73x1.05=
3863@ peak torque

Compare that to;
the standard A833. For the same 30mph@4000 in first; the standard 2.66low gear box would need 4.10s, and 1.92 second would then be 65@6400. The starter gear is 4.10x2.66=10.91 which is very good. But 65@3300 cruising. And the GVod would reduce that to 65@2600
Now how many on-road ftlbs at zero mph? With same engine, 10.91x280=3055ftlbs@2400rpm,increasing to
3930@peak torque

or the Commando box; using 3.55s, you get 65@5500 in second gear, giving you a starter gear of 3.55x3.09=10.97,very nice. And 30mph@4100 in first gear, also very nice....if a lil high. But again 65@2900 cruising and the GVod would reduce that to 65@2240.
Now how many on-road ftlbs at zero mph? With same engine, 10.97x280=3072 ftlbs@2400rpm increasing to
3950@peak torque.

So many ways to skin the cat; but you gotta admit the A999 is pretty clever for a two-gear streeter; 4100ftlbs at zero mph.......... just try and stick that!
I coulda used 3.91s with the auto for a better rpm at 60, but the A833/2.66box woudda never been able to stay in second to 60, on account of the 7000 plus rpm trap;(and there's almost nothing worse than seeing the guy you just wasted to 55, now, after the shift, come sneaking by you at the line). The Commando box is about perfect at 60 for a 224*cam say.
BTW, 360 ftlbs at peak-torque is only ~260hp, making that teener possibly tickle 330hp@5000 item... so it's not a monster,(1.04 hp/cube) just a sweet lil driver.Since it's the same engine in each example, the real-world torque numbers don't matter, you can just compare the percentage differences.And as you can see, the 30mph torque is within 2% from best to worst; that's because I tried to equalize the rpm at at 30mph, at the expense of all others.

Jus thinking out loud