Well, I found me a good one! We bought a piece of land that is quite literally a junkyard. Had a house we tore down, and a bunch of trash on it. Called the county and got free unlimited access to the landfill for the next 2 months. Called the cleanup crew and they wanted THOUSANDS to load and haul everything off.

So instead, my brother in law bought a skid steer, and I bought a dump truck! 1978 F700 with the Allison automatic tranny, 391, air brakes, 4 new rear tires, eaton 7.17 rear, full towing package including trailer brakes...filled her up with gas, checked the other fluids, and ran her home 55-60 mph the whole way (45 minute drive).

 

Well if ya don't have a Barn than build that first so ya can drag the 8N and old ford into it and start workin on em.

 

Looks good.

How many mpg do you get?

 

Nice looking truck! We used to have about 4 of those trucks (with hoppers on the back) for my Grandpas lime business back in the 60s and 70s. Now we only have one left. It's not in as good of condition as yours, but hopefully one day I can help restore it in memory of my Grandpa Joe.

 

Did you mean gallons per mile?

No but really, fuel gauge is broken. tank was only kinda full. no idea what we put in, or whats left.

 

Well...it may not be a 391. Went to get filters and fluids today and the bill was over $100 with just the filter. It was some 10" tall monstrosity, and I knew ours wasn't that tall. I told him to hold on, went home, grabbed all the part numbers and got everything out the door for about $60.

So what engine do I have, and how do I go about identifying it? This link shows a data plate, but where is that plate located?

Heres the air filter part no.


This engine looks just like the 391 in the link above




Filter(s)? I got a replacement for the black one (FRAM TG8A). Is the white one a oil filter as well? ****...just saw that now. Back to the parts store!



Is it possible that it is a 391 with a different air filter? Or is it more likely an engine swap? HELP! Thanks in advance!


EDIT: Just looking at these pics now, looks like spark plug wires need replaced soon as well!

 

Look at the sticker on the passenger side valve cover to confirm engine informatio. You never know if it got swapped out and if so, it may not be what the truck vin# says it should be. What you are calling a white filter appears to be the fuel pump mounted fuel filter. It unscrews and there is a replaceable element inside.

 

Yeah looks like fuel, good luck unsrewing the canister. They almost always seize on and usually you crush them during the removal process.

 

It's been years since I saw a 391, but I think that's what you have. I'm going mainly by the unusual thermostat housing. One of the guys in the 'big truck' section may be able to help.

As for removing the fuel filter canister, I use a cloth strap wrench and small ratchet. If the canister doesn't want to come loose, GENTLY tap around it where it threads onto the fuel pump. Unless it's been on there for years without being removed, it should come loose. When I screw it back on I put a dab of grease on the o-ring and threads to prevent it from seizing.

I think they used to make a wrench to remove the canister. It fit into the three small indentations in the bottom of it if I recall correctly.

 

I do not recommend using bearing or axle grease on the filter gaskets. It drys out, gets hard and really sticks. It is recommended to put a lite coat of motor oil on the oil filter gasket. That would also work for the fuel filter. But Vaseline or white lithium is what is recommended. When relapsing the oil filter be damn sure the old gasket comes out with the old filter. Sometimes ya have to dig them out. Same with the fuel filter. And no one has yet said that Fram filters are the worst ever. I thought it should be a PH8A Fram. Anyway after the first 100 miles or so I would change the oil again and put on a Ford Autolite filter. A ford dealer should have both filters or a Napa store.

 

Looks like a 391FT to me.

 

That's a good looking rig, looks like someone took good care of it! I was surprised to see the Allison. The usual 4 or 5spd stick can be quite the handful with a 2spd rear thrown into the mix!

A WIX filter (NAPA and Carquest premium brands are made by WIX) are also excellent and are a lot cheaper than a motorcraft. 15w-40 Rotella or DELO diesel oils are also excellent oils for these old engines.

The 391 is part of the FT family (very closedly related to the FE enignes 360, 390, etc) The problem is they all look pretty much identical. It could be a 391, 389xd, 361 or 330HD But the paperwork says it's a 391, so it probably is. Parts store catalogs can be funny with older trucks, certain things get omitted or changed or it's just plain wrong.

Sam

 

X2 with ya Sam. If ya can take the Fram filter back and get most anything else. I was an owner of a small chain of repair shops. I have seen Fram filters do some very crazy things that no other filter ever has. And none of it good or pretty. Pretty messy when they split down the side and an purge the crank case oil on the road.

 

Wix are best but walmart sells motorcraft filters for less than frams... $4

 

That FRAM filter was pre-oil change. I got a NAPA special and NAPA 10w-40 that we are gonna run for 100 miles and then swap out with the good stuff.

Put the air filter on, and did the oil/filter change, and she runs A LOT better now. She ran fine before, but opening up that air filter really let her breathe.

Drained the air tanks last night. Don't think that's been done in a LOOOONG time. Lots of muck came out, and it smelled like a lot like fuel...is that normal? Also required some gentle persuasion from some baling wire to get more gunk out.

The only major thing left to do is fix an exhaust leak and valve cover leak. I have the gaskets ready. Not sure I want to mess with the header bolts...I've broken them before! Any tips would be wonderful! Heat? WD-40?

Valve cover should be relatively simple...and I'm replacing spark plug wires tonight. Also plan on draining that eaton rear, and filling her back up with goop. That's some nasty smelling stuff.

It IS a 391, verified by you guys, and the sticker on the valve cover.