FUEL TANK CAPACITY 1982 K10 4x4

[Beast496]

Except the unusable fuel is just that, so it doesn’t matter.
I am pleasantly surprised though that virtually 100% of the stated capacity is useable in these trucks though.
In testing both the 77 and 86, I can run it down to where the needle doesn’t bounce up off E at all and have put 19.xx gal in the 20 gal tanks, prior to actually running out of gas.

I'm in the process of testing this theory as I just replaced my fuel gauge, cleaned a bunch of grounds, so both tanks are reading what I assume is correct now. Will be going until I run one tank out(or as far as I feel comfortable), then see what it takes. Then the same for the other side. Thankfully, the big block loves to drink fuel so shouldn't take too long, lol.

 

[75gmck25]

The older tanks are not baffled, so how low on fuel you can go may depend on the angle of the truck and whether you are turning a corner. I was running low on one tank and turned a corner that also went up hill and the truck suddenly quit. Switched tanks and it started right up. That fuel can slosh quite a bit. Baffles in the 87 and up tanks are supposed to help.

 

[Frankenchevy]

OP, the length is a pretty clear indicator. If the rearmost tank strap is close to the filler neck end, you have a 16 gallon tank.

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However, if there’s a foot or so between the rear strap and filler neck, you have a 20 gallon.

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[83Stepper]

Overall lengths will tell you, quickest and easiest way to distinguish the 16 or 20 gallon tanks from themselves. Never ran across an OEM unit on these trucks with a drain plug. My 63 Galaxie 500 had a drain plug in the tank, but I don't recall ever seeing a GM product with a drain plug on any of the vehicles I've owned. The 16 gallon tanks are like 42" long and believe the 20 gallon tanks are like 56" iirc.

 

[AuroraGirl]

Not sure about the drain plugs. I have owned older vehicles that had them from the factory, but they were Ford cars. Not sure if GM did that at all. Just got to climb under there and check. Or the drains could be added.

only fuel drain ive seen is the kerosene oil drain plug on a tractor for draining the kerosene out of your oil after running because the kerosene doesnt combust properly and gets pushed into the crankcase

 

[AuroraGirl]

Dual 16gal in a long bed. Not horrible, but weird…can I pay the extra $5 per tank for 20s please?
Bout as dumb as the GMT800s. Had a short-bed crew LB7 with like a 26 gal tank. Fckin pathetic. At least Ram and Ford have pulled their heads out of their rear recently and offer big tanks on their HD pickups now for the last several years. Idk if GM has followed suit.

my extended cab short bed is the same tank i think. it hurts to watch the fuel gage especially in the first quarter of the tank
The truck mileage is low but its not as bad as i perceive it to be

 

[AuroraGirl]

The older tanks are not baffled, so how low on fuel you can go may depend on the angle of the truck and whether you are turning a corner. I was running low on one tank and turned a corner that also went up hill and the truck suddenly quit. Switched tanks and it started right up. That fuel can slosh quite a bit. Baffles in the 87 and up tanks are supposed to help.

baffled tanks have the benefit of making less fuel vapors by slowing down fuel movement as well
And if you plan to EFI youre already set on the tank design too