Hey guys, I'm starting to make a move on my '80 F100. For those who don't already know, it's been wrecked a few times and driven like a movie stunt car, so no surprise the frame is mangled a bit. I was still driving it until the 302 gave up the ghost (main bearings fried), so instead of tearing it apart and fixing everything, I decided on a frame swap.

I know a lot of you would say to just drive the new truck and forget the old one, but it is sentimental to me and the body is in very good shape. A friend's grandparents are looking to get rid of their old F150, which is either an '85 or '86. The frame is decent on it but the body is pretty bad. No damage, just rusty. It's equipped with the fuel injected 302 and AOD automatic, which I'd like to keep the 302 anyway.

My questions are, how difficult is it to swap between the trucks? Would I have to use the wiring harness of the new one or would my old cab harness plug in to the rest of it? Where exactly are the computers located in these old trucks? I'd imagine probably behind a kick panel in the cab or something, in which case would I be able to mount it properly in my '80 cab? And my most important question, my truck has a C4, that was just rebuilt about 6k ago. I really like the C4 and was wondering if it would mate to a newer 50oz 302? My '80 302 is of course a 28oz imbalance, so I know I'd be good with the early 302's or a 351W, but is there any chance there's a flexplate to make it work with a '81+ 302?

Thanks for any and all help guys, I miss my old truck, I just wanna drive her again!

 

I can't answer any of your questions, but will respond nonetheless. The location of the computer varied significantly. I didn't think the 80 trucks had a computer, as the first ones I was aware of in the 49 state models was 82 and they were under the driver's seat. By 85 they were under the dash, roughly in the middle. But I don't know when they changed nor if there were other locations.

 

By 92 they were under the dash on the drivers side so I can't imagine it changing a whole lot from 85.

 

both the uncles 84 351 truck and 86 460 truck had them located in the middle of the dash underneath

 

Flexplate stays with the engine.
The C4 Torque Converter should bolt up.

Do you want to keep the fuel injection?
Or swap your carb/intake onto the newer engine?
If your current truck is DSII it would be easier to stay that way, I think.

 

I agree, I would strip the fuel injection stuff off the later 302, put a nice little 4bbl intake and carb on it, and drop it in with your c4. No wiring to mess with at all. No electric pumps and high pressure fuel system, you can use your old fuel tank from the f100. You can take the front of your old engine apart to get the timing cover and the eccentric for the fuel pump, take the front cover off the efi engine, put a new timing chain set on it, new oil pan gaskets, put the older timing cover on it, new gaskets and seals, paint it all up and drop it in. Use your old fuel lines from the 80 frame, etc.

 

X3. As said, I don't think the 80 should have a computer, so the easy way would be to carb the 302. Put the 80 cab and bed on the 85/6 frame, bringing with the cab its wiring. Swap fuel systems, inc tank(s) and lines. Should be good to go.

 

Well to be honest the EFI 302 in my '92 has kind of grown on me, so I figured I'd keep the fuel injection components of the '85 truck. I was planning to use the '85 wiring for my '80 cab, so long as there wouldn't be any issues with that. The '80 cab harness is a little funky. I wasn't sure where the computer was located was the main thing, to be honest I didn't even know where it was on my '92. No, the '80 has no computer whatsoever, my question as far as that went was if I could mount the '85 one properly in the older cab, in the same manner as the '85 cab, specifically the computer for the EFI 302, not the feedback systems on the carbureted engines.

Wow what a mouthful that last sentence was.

Anyway, the question about the C4 was if the TC would bolt up to the newer 302 flexplate. I thought they were specific to what trans would be mated up to it, and I don't think I've ever seen a 50oz 302 mated to one. I didn't know if they made the proper 50oz plate that mated to a C4. I'm sure you could mate them to the 351's all day long since they stayed at 28oz.

Just as a disclaimer to the whole carb -vs- injection debate here, I do much rather have a carbureted engine. I do love the simplicity of the early style SD EFI system on the '92, but I could get a pretty sweet tune on the '80 with just a wrench and screwdriver. I figured FOR NOW the EFI would be best for simplicity sake, as the truck will be getting a 427 stroker in the next couple years. The 427 being a smallblock Windsor was the whole point of sticking with a 5.0 or 5.8 equipped truck.

I had at one point decided on a 6.9/4spd/4x4 setup on an F250 frame, but I want to build a streetable race truck instead. I figured a 427/built C4/4.10's or 4.88's should make a pretty interesting build, and it would be a direct bolt in pretty much on the '85 F150 frame.

 

Why not a C6?
It would hold up better.

 

The efi is going to hold the whole show up, ,messing with all those wires. I don't particularly like the older efi setups myself, and certain parts are starting to get expensive and may be hard to find someday. And you will have no use for it when the larger engine comes into play, the stock efi system isn't suited for big changes. So if you go to a carbed setup with the 427, then you have to mess with the fuel system all over again, messing with the in tank fuel pumps, the fuel pump on the frame rail, etc.

 

Amen. EFI is good today as they have the kinks worked out. It wasn't back then, not by a long shot. I would put a modern EFI system on something, but no way would I put an 80's or even 90's stock EFI system on anything.

 

Yes, modern, multiport EFI just rocks!