Found about every other tank option but the one I need. Rear tank on early '77 F-250 4x4.

 

Because there is no such thing as a stock rear tank or sender for a highboy. Some one swapped it in. They only came stock with the in cab tank. You'll have to drop the tank and hope there is a ford part number on it. Either way they make aftermarket bolt in senders that have the correct ford ohms.

 

You want the 10ohms sender.

 

LMC trucks....

 

Go here and read up on the fuel tank sending unit test, then read more on how to drop it. X2 on the early HB does NOT have a aft axle tank, 77.5 does.

https://www.ford-trucks.com/forums/1...then-some.html

Have you ever been to the HB compilation page? https://www.ford-trucks.com/forums/1...ml#post1437578

Go here to locate the parts, scroll down to "Parts Vendors & Resources"

https://www.ford-trucks.com/forums/1...l#post14213910

 

I bought truck from original owner, he said it was a dealer install. How did they get the switch wired in on the dash panel like it was factory? Thanks

 

The factory wiring from another truck was more then likely used. As far as a rear tank goes in a high boy I do believe it was never offered as a factory accessory or otherwise. You however can swap in a bronco II tank or a tank from a super camper special, and have it look factory.

 

Quote: "Highboys came only with in-cab gas tanks, and optionally, with an
additional side-mounted gas tank, but never with a rear gas tank. A rear
gas tank is too wide to fit between the narrower 33.5-inch-wide rear frame
rails of the unique Highboy frame, and can only fit between the
37.5-inch-wide non-Highboy rear frame rails.

All F-series light-duty pickup trucks during 1956-1972 had in-cab gas
tanks. In 1973, Ford moved the gas tank to the rear under the bed, except
for Highboys. 1977 was the last year for the in-cab gas tank, because US
vehicle safety standards outlawed it. Make sure the filler neck grommet
remains completely sealed against the cab, and occupants will not smell
gas fumes. If both the cab and gas tank are breached in a serious
collision, the occupants probably will not be alive to worry about the
potential fire. In this respect, the gas tank is safer in the cab, since
it is less likely to be breached in the cab than under the bed, especially
while off-roading."

Could of been a dealership installed tank, but it sounds like none a normal set up. Hopefully dropping the tank and pulling the sending unit you can get some Ford part #'s.

Does the bed have a exposed filler cap or does it have a filler cap hinged gas flap?