Are fuel necks interchangeable in square door beds?

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AuroraGirl

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I got a 81+ whatever bed which has the fuel door on passenger side instead of driver/both, and I have a 1980 tank, and I need to put a new filler on. I have a 1978 filler, 2 of them actually, but that wont mount nicely. I can buy the proper filler from IFN supply but Im not sure if it will bolt to the opening. I have bedsides from 78 and another one from pre-78 but i dont know how involved that would be to change(surely more than filler neck?)
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LMC lists their cutoff as square/vs circle, but another sources say when the neck got larger or the whatever the mounting ON the bed changed. anyone have the scoop?
 

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The bed mounting for the filler changed in '84. In '84, the neck got a perimeter flange with three mounting tabs that secured it to a plastic housing.
 

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'84 and up is on the right:
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Can a 1978 to 83 then fit on the hole? It looks like maybe the holes line up it just doesnt fill the "trim" part where it seals it up?
 

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I got a 81+ whatever bed which has the fuel door on passenger side instead of driver/both, and I have a 1980 tank, and I need to put a new filler on. I have a 1978 filler, 2 of them actually, but that wont mount nicely. I can buy the proper filler from IFN supply but Im not sure if it will bolt to the opening. I have bedsides from 78 and another one from pre-78 but i dont know how involved that would be to change(surely more than filler neck?)
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LMC lists their cutoff as square/vs circle, but another sources say when the neck got larger or the whatever the mounting ON the bed changed. anyone have the scoop?
 

AKguy

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I have two of the “saddle” type, one for the main and aux side tanks, and used a flanged (circle) version for my additional tank in the rear. Just used some flat bar and a little welding and they mount fine.

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I replaced the hokey screwd on cover for the passenger side filler and added one to the driver side rear using cut outs from donors.
I flanged the new opening, applied panel adhesive and used clecos to hold them in place.

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HotRodPC

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They do interchage as far as sides though. Provided you have the correct year, they will work for either left of right side. Stepside bed is also different and usually hard to find.
 

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I replaced the hokey screwd on cover for the passenger side filler and added one to the driver side rear using cut outs from donors.
I flanged the new opening, applied panel adhesive and used clecos to hold them in place.

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I've cut a whole door set up that I'm having to add to a bed that is a driver side only. So I cut the door off the passenger side of another bed that was being scrapped before I tossed it.
 

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Check the filler neck hose diameters also. I found the later tanks, have a larger diameter filler connection, than the '76 style filler neck that I used.
 

HotRodPC

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Check the filler neck hose diameters also. I found the later tanks, have a larger diameter filler connection, than the '76 style filler neck that I used.
Yes, because some are unleaded only, some are diesel and the ones on my 86 are wide open with no restrictor cuz it could still run on Leaded gas in 86 being that it was a 3/4 ton and didn't yet require Cats for that GVW rating. That's another reason I always prefer the C20's. Alot less emissions ********.
 

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Yes, because some are unleaded only, some are diesel and the ones on my 86 are wide open with no restrictor cuz it could still run on Leaded gas in 86 being that it was a 3/4 ton and didn't yet require Cats for that GVW rating. That's another reason I always prefer the C20's. Alot less emissions ********.
It was lucky I bought new hoses at the time, I managed to get the new pliable, smaller '76 hose, to stretch over the larger tank connection. I didn't know the size difference when I bought the tanks. The used tanks I got came with the filler necks with the plastic adapter to the body and a screw on cap. So what year are they?
 

AuroraGirl

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I shall just forgo the proper fix and install big bertha

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AKguy

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Looks prehistoric
 

AuroraGirl

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Looks prehistoric
i managed to see my own thread in similar threads. Fun fact, its the auxillary filler neck for a 1967 ford f100 camper special that the factory auxillary tank(the main 10 gallon tank in the cab wasnt cutting it for a lot)
 

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