Which is the correct fuel tank ?

[HotWheelsBurban]

Dad's 75 GMC Sierra Classic had a factory tank on the driver's side, 20 gallons IIRC. The dealership sent it to another shop to have an auxiliary tank added to the passenger side. That shop didn't do such a great job; the neck stuck out too far and we always had problems with the switching valve.

 

[idahovette]

My 75 K20 came stock from the factory with a single 20 gallon tank on the Passenger side. If you wanted dual tanks, it was an option. Then you got the extra tank on the drivers side.

 

[AuroraGirl]

IIRC The options were:

1 single 20
1 single 20 - 1 single 16
2 - 20's

My Dad had one such truck a 78' K20 with one 20 on the left and one 16 on the right. With that said I would install 20's on a long bed regardless of what came with it for the extra 4 gallons.

seems a little weird to have to order both tanks as long you would think orderring extra capacity tanks would give you both lol

 

[AuroraGirl]

Dad's 75 GMC Sierra Classic had a factory tank on the driver's side, 20 gallons IIRC. The dealership sent it to another shop to have an auxiliary tank added to the passenger side. That shop didn't do such a great job; the neck stuck out too far and we always had problems with the switching valve.

did the truck use a manual valve or the electrical solenoid?

 

[HotWheelsBurban]

did the truck use a manual valve or the electrical solenoid?

IIRC it was a manual valve, but it's been a looooong time since we drove that truck. Got parked(inside) in '79 after getting wrecked, and after being in a couple different buildings it got sold in 2016.

 

[AuroraGirl]

IIRC it was a manual valve, but it's been a looooong time since we drove that truck. Got parked(inside) in '79 after getting wrecked, and after being in a couple different buildings it got sold in 2016.

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probably had this bad boy under the truck with a cable running to it

 

[Wallace6]

Yes I believe you are correct on the early models

 

[ChuckN]

IIRC The options were:

1 single 20
1 single 20 - 1 single 16
2 - 20's

My Dad had one such truck a 78' K20 with one 20 on the left and one 16 on the right. With that said I would install 20's on a long bed regardless of what came with it for the extra 4 gallons.

Sorry to hijack, but would that mean my ‘81 short bed single tank would be 20 gallons then? Or did they sometimes put in a single 16? Just curious, I never really let it get too low since the ethanol free station is only a couple miles away.

 

[HotWheelsBurban]

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probably had this bad boy under the truck with a cable running to it

Probably; I remember the lever under the front edge of the seat(mounted to floorboard?) and it seems like it would stick. Maybe the cable or mechanism needed lubricant?
I think the later trucks (78 & 81)had the toggle switch in the dash next to the ashtray; where the rear window switch is on a Burb.

 

[SirRobyn0]

Sorry to hijack, but would that mean my ‘81 short bed single tank would be 20 gallons then? Or did they sometimes put in a single 16? Just curious, I never really let it get too low since the ethanol free station is only a couple miles away.

No those I gave earlier were for long beds only
Short beds got 1 - 16 or 2 - 16's. 20's won't fit a short bed.

 

[SirRobyn0]

So I guess I should give all the configurations I'm aware of in one post:

The options for long beds were:

1 single 20
1 single 20 - 1 single 16
2 - 20's

Short bed options:
1 - 16 or 2 - 16's. 20's won't fit a short bed.

 

[ChuckN]

So I guess I should give all the configurations I'm aware of in one post:

The options for long beds were:

1 single 20
1 single 20 - 1 single 16
2 - 20's

Short bed options:
1 - 16 or 2 - 16's. 20's won't fit a short bed.

Thanks bud!

 

[AuroraGirl]

Probably; I remember the lever under the front edge of the seat(mounted to floorboard?) and it seems like it would stick. Maybe the cable or mechanism needed lubricant?
I think the later trucks (78 & 81)had the toggle switch in the dash next to the ashtray; where the rear window switch is on a Burb.

the 1974-1975 with manual valve also had a rocker switch for the fuel gauge only

 

[HotRodPC]

short bed trucks would get a 16 gallon but that means someone put a short bed tank on yoru truck at some point.
If you have long bed, your truck takes 20 gallon tanks. Get the right year and make sure your filler nexk and all that is right too

Yes, shortbed trucks only get 16 gallons tanks, but I have seen 1 long bed truck that came with 2 16 gallons tanks OEM. IIRC, it was an 84 C10. I actually kept them cuz I had plans to use one of them on my build so I'd have room to mount an air compressor under the bed on the frame rail.

 

[HotRodPC]

BTW, there is no left and right tank. Tanks fit both sides.