79 I6 swap to V8 or Injected 6
 

I"m looking at swapping out my 79 straight six for either a carbed V8 (302 most likely) or an injected straight 6. I like the straight 6 quite a bit, so my question is this. If I bought a donor truck with the six in it like this one 1995 Ford F-150 Pickup Truck - Kitchener / Waterloo Cars For Sale - Kijiji Kitchener / Waterloo Canada.

1. Would the newer 6 bolt right in the same way my 79 does?
2. Would the bellhousing be different? I have a 3 spd on the column and this is an auto... I want to keep the 3 speed.
3. It would be a fairly easy swap just to take the engine, all the wiring and exhaust work and throw it in my truck, right?

The blocks are identical except for the mechanical fuel pump on the older blocks, so it will directly bolt up.
You will need to mount the ECM and dash harness in the cab, and to keep it even simpler mount the newer gauge cluster in your dash as well. The less re-wiring you have to do the better.
You will also need to use an electric fuel pump, the 300's need around 45 psi fuel pressure, to keep it simple you could mount the FI trucks tank and sending unit and even use it's harness.
But I would only bother with the swap if you were swapping in an MAF 300 and not a speed density setup.

Ok, thanks. So for it to work well, I would need to swap the gas tank, fuel pump, gauge cluster (would it bolt in properly on my dash?) and the engine/wiring. I would also plan on swaping out/redoing the exhaust to split and dump in front of the rear wheels. How would one tell the difference between a MAF and speed density engine? is it by the year?

This isn't a direct swap, I'm just trying to word it as simply as possible, a gauge cluster is definitely not going to bolt in, nor will a fuel tank.
Your still going to need to do quite a bit of wiring and fabrication.
MAF 300's were in 96 and some 95's.
If I were you I'd build up the carbed 300.

Ok... Only reason I'm considering the swap is cause I have spent forever trying to figure out various issues with my engine. I am stuck on a really bad knocking at low RPM, and I'm hopefully borrowing a compression tester next week to check compression, cause I've checked timing, and the problem goes away at higher RPM. I'm going to diagnose my engine before going ahead with anything, but If it's gonna cost me over 100 bucks to fix my engine/ a fair bit of time, I'm just probably gonna do the swap cause the fuel mileage will be improved quite a bit, and I can just part out/scrap the donor truck.

Fuel system isn't too bad if you have a donor truck. The 90's rear tank is a bolt in, the fuel lines for a single tank truck make it easy, you don't need to swap dashes. You will have to wire for the PCM and such things. The pivot for the clutch linkage that mounts to the engine is not drilled out or cast properly in the newer blocks. I had to have a special pivot ball made to work in the new block because I had to oversize the hole and thread it. Exhaust will have to be re-worked a little. Love my EFI 300 in my 78'. I added the M5OD trans to which will involve adding a hydraulic clutch setup. The old chassis harness is mostly seperate from the engine harness. You can strip out the engine harness and only need a few hot in run and start kind of connections.

Ok, sweet! I am planning on a 5 speed down the road, but that could be years. I love the look of your '78! How did you figure out which connections needed to be made hot in run and stuff? Do you remember what they are, or is it documented somewhere on the internet? My exhaust needs to be re done badly anyway, so that's not a huge issue.

Your best friend will be the ford wiring manual. I just got a hold of them and sorted out the wires. I got an underhood fuse box from a newer expeditionwhich makes like easy cause it will have relays and fuses you can use to interconnect the old chassis harness and the new engine harness with some splicing. I don't remember off the top of my head but I only have like 4-5 relays and fuses and use the 2 exsisting wires from the old trucks ignition switch to actuate relays to power up the computer and fuel pump.

Ok, thanks. The wiring for the 90's engines is still pretty simple isn't it?

Yeah, there are only about 10 sensors and actuators to deal with.

TPS (throttle position)
MAP (Manifold Absolute Pressure)
ECT (Engine Coolant Temp)
IAC (Idle Air Control)
EGR position
EGR vacuum control solenoid
a few ignition control wires
injector wires
O2 sensor
maybe one or two more I forget.....

I can't recall if the 95 trucks still use the thermactor air system for emissions or not but there is a way to get rid of all that stuff. And the obvious alternator and things of that nature.

Fuel Injection is very easy in these trucks. I love my efi 460. As long as it's the rear tank setup its direct bolt in except for the sending unit is the wrong ohm range for the factory guage.

Only two wires to really worry on these trucks and as far as I know they are all PRETTY MUCH the same but dont quote me on it.

Red/Green is hot in run and start
Red/Blue is hot in start only.

Call me silly or lazy--I would fix your existing engine with a rebuild, add a 4bbl intake, mild cam, EFI exhaust manifolds and drive it for less time and money invested..... just a thought, ymmv. :-drink

To get the gas gauge to work swap with one out of a late model Van. The fuel injected E series used the same dash as our trucks.

Well, it really depends on what it needs- I'd probably be able to do the EFI swap for less than $200 when all's said and done.

Sorry, what's the reasoning for swapping the fuel tank again? Can I not just install the electric fuel pump in the engine compartment or on the rail somewhere and use the existing tank?

Fuel pumps dont like to have to suck the fuel out of the tank, even if you mount it "lower" than the tank itself you still have go over up and over through the pickup in the factory sending unit. It makes the pump work ten times harder.

Ok. so the current manual fuel pump is able to just deal with it?

$200 to swap in an EFI motor? Dream on and good luck with it.

Well, I have a line on a complet donor truck for $500, all I'm doing is an engine swap, no tranny stuff, I'm doing all the labour myself, and I'd be parting out or scrapping the truck when I'm done. Is there some other major cost that I'm missing? cause I'm fairly certain that the donor truck would have everything I need...

Always expect the unexpected. Maybe you get it all done and running the second day the fuel pump craps on you. Im a look on the bright side kinda man but you have to always "be prepared".

Yeah, and that tends to be my luck :p Oh well, I guess I just have to learn to expect that when I'm dealing with a truck that's 35 years old. On the topic of the 95 fuel tank, does it have an extra pump in the tank or somethin? or is the high pressure pump in the tank?

I believe 1990 is when they made the switch from one in tank and one rail pump to just a single high pressure pump in the tank. I went this route becuase it saves wiring another fuel pump lol. Yours should be just a single in tank pump.

Just remember also that even though your updating your 35 year old truck your updating with an setup that is almost 20 years old as well.

Yup, which it means it should still be simple enough for me to fix :p

Will the front tank not work in to the 78? Are they bigger in the mid 90s?

The frames had a redesign and the tanks are totally different.

Thanks Davewild.
I have a 72 f100 with a 78 front tank installed I knew the back one would not fit as the rear of the frame is 4 inches wider starting in 73. I was thinking a fuel injected tank from the mid 90s might fit in the front to fun a EFI 302 That I am looking to install soon.

Thanks Pat.

Yeah the 73-79 front tanks are no where close to the 87-96 front tanks. I have both here as I wanted dual tanks in my truck and had to switch to a single rear tank.

Before that I did run my stock 78' tank with a added return line and used an aftermarket MSD electric fuel pump to pull out of the tank. It worked OK but when the tank got about to 1/4 I started pulling air as the fuel sloshed around in the tank. So you can pull from the tanks with one pump but as stated it isn't very good to do.

The stock diaphram fuel pump is more of a positive displacement pump that can creat a little bit of suction to pull fuel. The high pressure vane style pumps used in EFI applications really need a sort of suction pressure head to work best. In other words they need a slight pressure on the suction side of the pump to function properly. You run into problems when a vane pump runs dry as it does not move air very well at all. You can get by if there is liquid in them as it will create a syphon kind of effect but once again not ideal. I ran my truck that way for 12 years. I have had the EFI conversion on the truck since 2000.

I do love never having to mess with that damn Carter single barrel!

Thanks Davewild,

I guess I might have to see if I can get a fuel pump out of a newer truck to fit in to a 78 style tank. As long as the depth is similar it should work even if I have to buy a new tank for the 78 and weld in the lock ring for the fuel pump. Safer to weld in a new tank rather than playing with a older tank.

Thanks Pat.

That was my plan as well...but the tanks are just so different it's going to take alot of fab work to make it happen. I can post of some pictures of the tanks side by side later today if I have the time.

Thanks Davewild, Some pictures might help me.

Thanks again....Pat.

The EFI tank is the one with the bigger hole

http://img.photobucket.com/albums/v4...ps7ca6681e.jpg
http://img.photobucket.com/albums/v4...psbab18eb8.jpg
http://img.photobucket.com/albums/v4...psc1fff561.jpg

Thanks for the pictures. I guess I have some more thinking to do about a fuel tank for my 72 that I want to install EFI.

Thanks Pat.

Ok, so I got some solid data on my compression test. It was done Dry and with engine cold cause I didn't have time to let it warm up. They are as follows. 1 (155psi) 2 (152psi) 3 (165psi) 4 (160psi) 5 (170psi) 6 (160psi)