I'm unsure of the auto bolting up to a 2.0. I do know the 2.0 is a narrow block and will bolt up to the 5spd truck narrow trans. I was going this route with a red top 6bolt until I had to sell the engine. But if you need any and all info on this swap, check out
www.hotrodcoffeeshop.com. This site was started for just this swap. Lots of important info you will need like wiring, parts, etc. Hell, you can even get a wiring harness too if you have a stocker.
As far as the 2.4, it's the way to go with the stock engines by looking at hp numbers, efi and all that on paper. I have a 2.6 starion block that came out of mine that I was going to rebuild...then got the red top....now going to run a 2.4 drivetrain to get here running. Later on I'll look at a 302 swap into it if I hang on to it long enough. (I'm missing my 72 F100 that was stolen, want to play with something older)