Oh well if you already have the A833, And 3.55s, that's a no brainer, just stuff that A833 in there, with a regular clutch.
As for the 340,
keep in mind that Adding power takes rpm, which almost always takes torque off the bottom. Depending on what you do for a cam and cylinder pressure, you can loose as much rpm off the bottom as you gain on top.
In a street car, this is usually not a good thing, which is why I started with a 360.
If yur not careful, you'll be into 3.91>4.30s in a hurry; and then you'll probably want an overdrive.
If you go to far, then you'll probably end up with an automatic.,,,, for several reasons;
1) with a manual trans, as the idle-rpm goes up, you can't drive slow anymore. 800 rpm with a 2.66 low and 3.55s is about 6.8mph. So parading is out, and you might have to slip the clutch out like a Mustang, because of the lack of Idle/low-rpm torque.
whereas with an automatic; you get
2) more torque multiplication in the convertor, that
3) allows you to run a lil less rear gear, to
4) reduce your hiway rpm.
5) pretty much ideal, would be a 4-speed automatic with a Lock-up converter is The Mopar overdrive has a ratio of .69, which means that you can run say 4.30s and get yur bottom-end back, yet she will cruise like 2.97s, for 65=2400; perfect for a modest cam.
With 4.30s in the back, the engine shouldn't be particularly fussy about the stall, in a streeter.
Yes you could run that with 3.55s for 65= 1980, but the engine will NOT get you any efficiency down there. it might actually lose mpgs; actually I'm sure it would.
Plus, the starter gear will be 3.55 x 2.45= a paltry 8.70, so even if the TC has an internal hydraulic equivalency ratio of 1.8 to 1, making your 8.70Starter feel like about 15.66 for a second; that will be brief.
I mean you could try it since they're already installed.
Personally
I'm not liking an HO 340, 3.55s, and a manual trans.
If I was stuck with a 340,
I'd get me a 4-speedLU auto, some alloy heads, run a modest fast-rate tight LSA cam, at high pressure. Now it's set up about right for a streeter, cruising at 65=2400; with 4.30s and overdrive. Badaboom.
If I had to use a Mopar-manual trans, I'd put a GVod on the back of a Commando, run a 3.73 gear, and use the GV as a splitter. Again, 65=2350
The ratios would be 3.09-2.41-1.92-1.5/1.4-1.09/1.00-.78
The first 4 will get you to 86mph @6000, 1.4 will get you 92 mph@6000
1.09 ratio will get you 6000= 118
about 95% of the time you would be shifting
3.09-1.92-1.4-1.09-.78, splits of .62-.73-.78-.72od......... Badaboom.
That's what I already did but with an HO360, 3.55s, and trapping about 5700.
Parting shot.
With a 340, a Mopar 2.66 box, and 3.55s,
I would go easy on the cam,
and rather pump it up to say 195psi with alloy heads.
Some guys will tell you that alloy heads do not require special considerations. To that I say, try running 195psi with iron heads, on the street with pumpgas, day-in/day-out. It's never gunna survive.
BTW, my 367 ran that on 87E10. yes at full timing.
This is NOT a brag, just a testimony.