A833 OD 340 4x4?

Oh BOY! there it is 4500ft
that's the problem.
that's worth about 20/25psi right there.

Now, it's unclear to me from your post whether you will be operating your truck exclusively at 4500,
or whether you will be just taking occasional trip up to 4500, and normally operating at some lower elevation..
You cannot build a normally-aspirated carburated engine to do both. And you normally have to rejet at about every 2000 ft change in elevation, and every 30*F change in temperature.

At 4500 ft, to meet your stated goals, forget the cammed-up 340.You will need more stroke.
You can get a very-high compression 360 with aluminum heads, into the ballpark, with a small cam ; (a solid-lifter type recommended);
but because of the 20/25psi loss in cylinder pressure from sealevel to 4500, you will have to set it up for borderline operation at the lowest elevation that you plan to operate it at, using the best gas you have available, and then at 4500 you will need to rejet your carb probably twice on the way up or down, and you'll have to live with the powerloss at 4500.
Or you can take the easy way out and just install a bigger engine, set up for some in-between elevation, at a lower cylinder pressure, but you'll still have to rejet when ascending/descending.

Your last option is to just supercharge your current 360engine; could be a super or a turbo, either way, but you still have to address the fueling issue.

But if you are only migrating a thousand feet or so, then you can cover both ends with a high-pressure 360, and a modest solid-lifter cam.