Long-off 340 build

The list you have and the thought process is very good.

The standard A-833 4spd is a very good trans. No weird gear drops.

The OD A-833 has slightly weird ratio spreads. A deep first gear and a tall final drive ratio due to the spread between 1st & 2nd & 3rd to 4th. 2nd to 3rd is a normal feel. You'll have a feeling like your winding out first to get to a good rpm for second and then again for 3rd to 4th.

The bell housing can be bought from Brewers. The retainer bearing is very large. And hard to find otherwise.

On 5spds. Tremac is a better plan though it is a bit more expensive than the other units listed which are probably at the junk yard and cheap.

(IMHO, go to a A-500 auto trans swap.)

On the other parts;

You can still get that MoPar dual plane? Wow!
My Hookers fit good on my Duster. A 2-1/2 system is an excellent t idea.

If you already have a V8 radiator, skip the aluminum radiator. Save money.

Rear end; If you have an 8-1/4, your good to go and go fast.

Brakes, factory discs set ups are good. No drums if your driving is "Spirted" or racing.

Vacuum pumps are used with big cams. But I guess it can't hurt. I see no real need for it as of yet.

You asked for a cam recommendation?
You'll get 50 different replies from 50 different people.

With a 3.55 gear & a unknown tire size given your goals, a nice and powerful street machine, I make this "General" suggestion;

Hyd. cam
Duration @ .050 of 230 - 236 on a 110 - 108 centerline with as much lift as you can get and the use of 1.6 rockers from Comp Cams or Hughesengines.

Add 4-6*'s for a solid cam.

You can start a cam search at Hughesengines.com