Hey all, i got a few questions about a 90 e-350 bus my dad has. Now this bus has a non-turbo 7.3 diseal, and its on its last leg, so we are interested in swaping in another motor (diseal perferably) so that we can use this bus as a tow vehicle (we have all the seats removed) for the 81 f-250 competition mud bogger that me and my dad built last year. And i am interested in what cna all be swapped in without have to do major surgery (have motor mount towers for a big block and small block ford motors), and we would like to keep the auto tranny in there if possible as its in very good shape.

Its a pian having to keep moving tools inside the truck when we can't watch them so thus the reason why we want to use the bus, cause we can keep everything inside and locked up.

 

I think the 6.9 and 7.3 diesels are the same size. I don't know if the trans will work on a gas engine. You can check with ford or your local tranny shop about that. Try ebay for another diesel, or maybe your local bone yard. I would keep the diesel. It will tow better. You can get more info in the pre power stroke diesel forum.

 

You're always better off keeping your rig if you keep it as stock as possible. The internal engine parts can be changed, intakes, exhausts, etc can all be improved. If it were me, I would look for a good used/rebuilt 7.3, and build from there. There has to be gazillions of those NaviStars around. ATS makes a good turbo, so does Banks and Bully Dog among others. Propane injectors for short bursts of power, nitrous (yea I know, SPENDY power), after all how much do you really use all available hp and torque ? You've got plenty of options. To change gas to diesel, or vice versa will be alot of work and will take alot of research. Go with a proven set-up, the stock one and embellish for what YOU need. The non-IDI 7.3 is a good motor, have it checked for cavitation erosion, but that's applicable on all Navistars I think. You have a good base, a good starting point, K.I.S.S. is always the best plan, peace, Ken