400 (6.6L) swap to EFI 351W (5.8L) questions before I tackle it
 

So I've been trying to figure out what I'm going to do with my 78 F250 4x4, outside of a average resto mod, I want a kind of "unique" power plant in this one.
So here goes nothing...
-i have the small block bell housing required
Annd that's it...lol

So I want to make a list of what I need
-EFI Engine, preferably a late 95-96, along with computer and harness.
-what can I do for motor mounts?
I feel comfortable with this swap, as I have had a 87, and a 96 and I have a good general knowledge of the system.

Any help, or advise I may want/need before I start buying/planning too far ahead?

Motor mounts: the existing frame towers will work with any year truck (not van) 302 or 351w engine mounts.

Fuel tanks on the newer trucks are pretty nearly the same size and shape as the older ones, so you could grab the tanks and lines off a newer truck, or add external pump and return line to existing tanks.

Could I use the 400's towers? Or will they set the motor too far down/up?
I'm not exactly sure I want it but the 5.0 is bountiful here so if need be one of those may go in until I can find a good 5.8. :/

A donor vehicle would be the ideal thing here since you need the complete engine, EFI, and fuel system. Just be aware that in the mid '90s the windsors were paired with computer controlled automatics for the most part and while using the engine without that trans is possible it presents some additional challenges. One way around these issues would be to use a 5.0HO Mustang computer.. which will run a stock or lightly modified 5.8 no problem, the computer connectors will have to be repinned but that's relatively easy with it out of the vehicle. Also note that the 1/2 ton trucks went OBD-2 in '96 which is a much more complicated system and the 5.8 was rare.. mostly 5.0 trucks. There are some 5.8 OBD-2 unique sensors on these trucks you will need. The upside of this year vehicle is that the computer can be tuned with a handheld device so deleting and modifying things is relatively easy.

So now I'm thinking about sticking with a 88-91 5.8... Or one out of a truck with a manual trans..
I'm also considering trying to find a 4x4 with a AOD or something of the sort..

Lots of thinking and planning left to do. Looks like fordfuelinjection will be my friend...

The engine wiring on the earlier trucks is much simpler and more of a stand-alone setup, but the early motors were LAME.. badly restricted with small cams.. which is easy enough to fix. The AOD was never factory installed behind a 5.8 but it will work and survive just fine with a some updates and a shift kit, and the wiring on the early 5.0 and 5.8 motors is identical so if you were to get a 5.0 truck for most of the parts you could still connect a 5.8 to it.

When you say "some updates"; what do you mean?

When it comes to transmissions the latest model you can find is always the best one to grab because it will have all the little updates that were issued over the years to fix everything from nagging little problems to serious weak points. Early AODs were really under built for truck use so if you want something that will handle that plus a larger motor it will need to be rebuilt to the latest spec at the very least and have a shift kit installed to firm of the excessively lazy factory shift pattern. There are other levels you can go to as well by transplanting much of the guts of a 4r70w into the case and by doing away with the stock coaxial input torque converter in favor of a non locking converter.. dependig how much abuse you want the trans to handle.

Does anyone know what I can do about towers? I have the 400's towers but will they work since the 400 is a "small block"?

Ok, so I measured my 96 302 and "mocked up" my 400 towers, if I measured right, it should put the 302/351 about one inch to the left compared to the 96.
Now, are these useful to me or will I have to make my own?
And did I even do right by measuring from frame rail to block, or did I waste my time?

Now that I think about it, I didn't figure in the actual rubber motor mounts when I measured, that could be where I'm coming up an inch short.. Hmm

Stock 400 frame towers, stock 302 truck engine mounts is what you need, so you should be good to go.

bcbroncos.com

This is mainly for EFI conversions in older Broncos but I have ordered a lot from them during my swap. I finally broke down and bought the universal wire harness yesterday for my EFI 5.0 swap. The throttle cable and transmission kick down cable kit they offer made life for me THAT much easier!