Some miscellaeous ramblings:
- Mustang 5.0-HO engines are arguably the best candidates for a swap. '89-'93 were MAF and had the highest HP numbers, AFAIK. The MAF system is dead easy to deal with in a swap - in fact the EFI HO engines must rank amongst the easiest EFI engines to swap into a non-EFI vehicle. Their electrical systems are almost completely self-contained, so you only have to hook up a few wires during the install.
- When mating a 'stang 5.0-HO with a 4-speed (NP435, T18, T19), use the later-model (post-'85?) 50-oz imbalance truck flywheel, clutch & fork, bellhousing, starter, and throwout bearing. You CANNOT use the Mustang parts - they won't work with those trannies. Small mercy: the pilot bearing is the same, at least.
- Mid-to-late '80s Ford trucks had a great hydraulic clutch setup with an external slave cylinder. The bellhousing for this setup can be bolted between most 5.0 blocks and most HD Ford 4-speeds.
- While the factory 'stang headers look cool, they interfere with the mid-'80s hydraulic clutch slave cylinder. Run the truck manifolds and save a few $, unless you're mud-dragging or something. You should get better low-end anyway.
- 'Stang 5.0s run 40psi in the fuel supply line, so get a pump that's good to at least that much pressure. And yes, you need a return line to the tank.
- Avoid Z&M - my experiences with them have all been negative, and IMHO their stuff is massively overpriced. I'd suggest using separate left- and right-side motor mounts (maybe with a removeable cross-brace) instead of their cradle-type mount. Sure, you should never need to remove your oilpan once the engine is installed, but if you ever do, you're SOL.
- For those of us who would rather walk hot coals than fork over the kind of money AA wants for an Atlas, Ford didn't provide many options for good t-cases. that bolt up to 5.0 powertrains. The EB D20 is okay, but you need a custom adapter to mate it to a 2wd NP435. The NP203 is a boat anchor, which really just leaves the NP205 (2:1 low range) and the NP208 (chain-driven), plus all the later-model NV cases.
There's a bunch of photos & stuff of my 5.0L & dual t-case install at my website, check it out if you haven't already, and feel free to email me with questions if I can help.
Hope that helps some of you,
Chris