I have a 94' F350 CrewCab 4x4 with the 7.3 IDI Turbo, it has an auto tranny, I think the E4OD( don't remember just now) and running 35" BFG MTs. It has 240k miles and I can get 15 mpg on the freeway with it if I keep the rpms below 2000.
I pulled a 35' camp trailer from SLC UT to Pocatello ID and still got 15 mpg, but I kept it at around 60mph the whole way.
When I got it I read piles on the FordDiesel forum. Some of the basic power tuning things were the Injection Timing. Stock calls for 8deg ATC(After )I think the reason was to keep it quieter. The guys on the forum said to advance it to 6-8 deg Before. When I first got it it seemed like it would pull hard up to 2000rpm and then the power dropped off dramatically. After I changed the injection timing it would run great up to 2500 rpm.
The next thing was the turbo boost. I think Ford set the waste gate at 2psi to just clean up the smoke. Adjusting the waste gate is pulling a tiny pin and turning the adjuster rod a few turns and put it back together. I don't remember how many or which direction to bump it up to 6 or 8 psi-ish. Some guys said they were running 12-15psi with good results.
The next big thing is larger exhaust...
With the IDI you can run waste vegie oil without gumming up the injectors like a DI would. When my oldest son worked at Dairy Queen, they would change the oil the fryers every saturday, he'd pump it back into the original 5 gal jugs and give me a call to run down and pick it up. I'd heat and run it through several filters, then run veggie in one tank and diesel in the other. It seemed to get the same milage and power, the engine just ran cooler.
If you already have the engine, put it in. Maybe try to find a turbo and do the other performance tweaks.
One of the guys on the forum said that running a heavy concentrate of fuel additive would clean out the injector pump and injectors. I don't remember the brand he suggested, but it's worked well for me when the engine starts running poorly.
this is a great thread, I was thinking of starting one with similar questions. How do you think the E4OD tranny would hold up in a Deuce?
The 7.3 has about the same displacement as the Multi Fuel, it's just a V8 instead of a straight 6.
I"m sure there are many other things to consider, and I'm not an expert on any of them.
I don't have one yet, but I've got the bug and think I need to build a Bobber. Maybe two and give one to Dad for X-mas.