The time has come... 440 freshen for B-body

I think you need to start with two boundaries in mind: The existing condition of the engine overall, and the honest budget. Notice nowhere is horsepower mentioned. You can't machine a block if you're not going to completely strip it and clean it after. So if the budget is small (understanding the 4spd swap and the rest of the car are equal priorities), inspect what you have. If it's good, ignore the compression part and expense of milling, pushrods, etc. Keep it simple. In the same line of thinking - those 3 speeds came behind the 383 4bbls and 340 4bbls. As long as you don't try to power shift them they can take a bit of abuse (personal experience here...) so I'd concentrate on the floor work and installing a 3sd floor shifter setup, then you can always run the 3sp until the 4sd is found or affordable. Another thought is the later A-833OD long tail. That will also work and give you OD. Anyway - those are my thoughts.