Need some suggestions!

The trucks pretty heavy and the convertor in it is designed to be tight even when you're hauling something. That beign said - I have the XE262 in my truck - much heavier, but otherwise stock 360 with bolt ons and it's a torque monster even with 31" Mud Terrains. I think in a 2wd truck 1K lbs lighter the 268 would be fine. It might be soft in a 340, but the 360's longer stroke will take care of any "soft". I think the 340 stick cam will be too small to make any real steam beyond the factory cam that's in there.
Also - whatever cam you chose - you have to replace the springs with what matches that new cam. no maybes. You have to. You will also want to grab (8) plain old valve retainers and exhaust valve locks and replace the valve rotators you probably have in that 360. I used Comp 901-16 springs on my 262. They'd work fine with the 268 too.