Not best, but optimum Transmission?

Clutch problems are not an issue, with your tires

Optimum trans for what?
Street? Street is all I know.
There are several points to consider;
They are arranged according to my preferences.

low-rpm torque, and stall
rear tires and gears
Starter gear requirement
hammer down at 32mph
zero to 60mph ET
rpm at cruising speed
engine powerband
Rpm of peak power
rpm at TrapSpeed
there may be more

Re-arrange to suit your preferences.

I can tell you what doesn't work;
a 292/292/108 cam in an 8/1 scr 360 cuber with 3.55 gears, any tires, and a 2.66low A833. This is guaranteed to make you pout. If you put a 727 into the mix with a stock TC, You will cry buckets of tears.
I can tell you what is guaranteed to tickle your innards and make you smile every time you stab the gas;
a 220 to 223 (at .050) fast rate hydraulic cam, in an 11/1 Scr aluminum headed 360 with any gears, any tires, any trans and, any TC.
On the street, Torque and TM (Torque Multiplication) are king.

General observations;
>The more torque you have at 32 mph at Kickdown, the more you are gonna need tires and traction. That is to say; with street tires and street suspension, it is easy to annihilate the tires, which results in lots of tirespin and slow ETs. If that's your thing, perfect.
> For me, I care almost nothing for dragracing, so I will never optimize my rear gears for that. But I do care about low-ET for zero to sixty. To that end, I gear my car to run outta revs, at or near the power peak, at or near 60 mph, in SECOND gear, having gone thru the power-peak twice. And so, I have to use a manual trans, cuz you can't do it with an automatic, even with wicked race gears in the back.
For example; say you had 3.55s, and a powerpeak around 5000, shifting at 5400, with 27" tires. Ok. the 727 will get 60=4000, just getting up on the power. Whereas the MT will be at 5100, right on the power-peak, for the Second time. So the M/T will put more average power into the exercise. If you can make it hook, you will generate a low-ET. But if you spend 2.44 seconds in the 60ft window, well then, the 727 car might smoke on by you.
With a stout 360, first gear is sortof a throw-away gear, only used to get into second. So for me, hammer down at 32 mph is a big deal. My A833 has the Commando 3.09 low in it, so 32mph is 4300, about at the top of the torque peak, but already on rising power curve. But in second gear, she cruises at 2700, so sorta quiet and relaxed, and un-assuming and the cops don't notice me. But when the mood hits and I downshift, it is instant tirespin, and bouncing off the rev limiter. I can only hold it there for 1 or 2 seconds, before grabbing second, which also goes straight to the limiter. By now the tires are warmed up, and the car is rocketing to my self-imposed speed limit of 60 mph, and perhaps 3 seconds has elapsed, maybe 3.5. Then it's hard on the brakes, and slam it into third. For me that is a rush.
>If you have a 727 with the same 3.55s, and a typical 2500TC;
32mph will be ~3800 in first gear at WOT; and ~2000 cruising in second. So at KD you might be right on the torque peak, ............ but you can't make it to 60 in first, shifting into second at about 45 mph. At which time your tires will have grabbed, and now your revs will fall to 3200, and your smokeshow is done. Yur gonna need one of four things; 1) more torque, 2) more stall, or 3) more TM.
>These lead straight to 4) an overdrive. The od will let you run; more gear, less stall, and make your engine perform like a bigger one. And the bonus is; a lower cruise rpm.

If you look on the bottom of the list you will get to the engine. I put them there cuz, for a streeter, the absolute power of your engine is not real important. When properly geared for zero to sixty, first gear is a smoke-show. So your engine needs to be on the power when it hits Second gear, and then you stretch second out to Sixty ( or wherever you decide to quit). So yeah, cubes are gonna make a difference, cuz they bring more average power to the table, if you can make the car hook. But power at 6000 is never gonna mean anything but nothing, if you don't get there. And in the meantime, you rob powerband and fat-midrange, to get that power at 6000.
So, IMO, forget the 292/292/108 cam! with 3.55s. The second-gear power peak comes at ~80 mph with an auto, ~83 with a manual.
And it makes waaaaaaay more power than your stock chassis can deal with. and you just end up with tirespin all the way there. If you gear it down to peak at say 60mph, this will take 5.38s.... and now you have two useless tire-frying gears. Ok, you like that cam? put it in a 273, to try and tame the tirespin. Or spend the coin on the suspension,to make it stick. But of course, that cam brings other limitations with it.

Ok I'll spill the beans, I have the optimum transmission.
For me,
And for my combo.
This comes after running just about every Mopar trans available before the A500/518s, and with just about every rear gear, and after hammering thru 3 different cams.
I have settled on; a 3.09low Commando box, with a GearVendors overdrive behind it, and 3.55s out back
The Commando ratios are 3.09-1.92-1.40-1.00 and the GVod is .78.
Splitting gears, I get a bunch of gear ratios that I can use in different ways, like this;
3.09-2.41-1.92-(1.50-1.40)-(1.09-1.00)-.78od,( GV ratios in red). That's 8 gears, but 2 of them,as you can see, are too close together to be both used, so I use one or the other as a 4+1 most of the time, and occasionally as a 5+1
So usually,I shift 3.09-1.92-1.40-1.09-.78; splits of .62-.73-.78- and .71into od
When showing off; 3.09-2.41-1.92-1.50; splits of .78-.80-.78
With 3.55s that 1.50 ratio gets me 93mph @6150rpm, in the Eighth.
The starter gear is a delightful 10.97. I have tried every imaginable starter gear from 8.59 to 15.08; and 10.97 is just right for my engine.
As for my engine; She is not built for absolute power. Nor even for a lotta power. She was built for monster low-rpm torque, a big fat midrange, modest power at peak, and the ability to rev out to 7200.