How many gallons of fuel does a stock tank hold?

[demian5]

Anything more than 10 gallons, and some hard right handers, puts most of the gas on the driver side of my bed.

[rvrfoot]

Maybe the 60 66 are different then the 67 72?

[leddzepp]

Everyone has a different answer every time this is asked

[toolboxchev]

Originally Posted by leddzepp

Everyone has a different answer every time this is asked

I know, my truck Haynes/Chilton manual says like 20 gallons. I can run it on E for a while yet have not ever run the tank dry.

Most I think I have got into it was around 18 or there about. I believe it has something to do with the specific gravity of fuel today. I have a tendency to believe it is sold by weight/specific gravity/gallon formula or something to that effect.

[special-K]

I have had many trucks and all have accepted over 20 gallons in their 17 gallon tanks

Must be the 2" fuel line I like to use

['72_GMC]

I heard there was a 38 Gallon tank available somewhere, for the Suburban, anybody know about this?

['68OrangeSunshine]

I have a '67 behind-the-seat tank in my '68 C/10. I replaced the OEM '68 tank when the ethanol-laced gas started getting sold, and decades of gunk [formerly solidified on the bottom] was being dissovled by the new formula. The tanks were identical in size and capacity. With a new re-pop sending unit, my guage needle started reading high. Totally full shows at almost 2:30 - 3'O'clock. A "3/4 tank" is really at about half, and it could be empty showing 1/4 left. I don't let it get low however.
I have filled them to nearly 22 US Gallons, up to the neck. Possible the later smog regulation-equipped tanks held less. IDK.
If I fill the '68 Stepside's tank to the neck [usually at night when it's cooler], I have to watch out for parking it level and in the sun, or the gas will expand and drip out the cap. Parking so the drivers side is higher, will keep the gas in the tank.

I have a stock belly tank in my '71 GMC Jimmy [like a K/5 Blazer]. While I have pumped 21 gallons into it, I think the gas pump was calibrated wrong. The belly tanks are smaller than the seat tanks. The Jimmy's gas gauge doesn't work, or the float is sunk. Because it would be a major project to remove the fuel tank skid plate, to access the top of the tank, I haven't bothered yet. The tan wire is disconnected so passengers don't think I'm almost out of gas. It reads at 3 O'clock constantly. I keep a log clipboard on my dash and note my To and From runs, fuel taken onboard and mileage and calculate my burn rate at less than 10 MPG. I try to keep it topped off every 100 miles.
Thought I ran out of gas a couple of months ago but it was a mechanical fuel pump failure.

[1968 baby blue C10]

Here’s a picture from my 1968 manual. Seems definitely 20 for 1968 anyways. I know mine holds a little over 20.

[BCOWANWHEELS]

My 72 c10 holds a little more than my 71 c10

[FirstOwner69]

My 1969 owner's manual also shows 20 gallons. The most I've ever added was 20.6 in 1970 when I was running on fumes near Mt. Rainier in Washington state.

['72_GMC]

Originally Posted by FirstOwner69

My 1969 owner's manual also shows 20 gallons. The most I've ever added was 20.6 in 1970 when I was running on fumes near Mt. Rainier in Washington state.

That Gas station near the park gets an extra $1/Gallon, From Washington State, I apologize for his greed. That is the whole point of wanting a larger Tank, that thing only gets about 8MPG and those gas dealers out in the country side can get really opportunistic in charging for fuel

[sick472]

I have worked with a few other sending units and gages/tanks on non-truck projects and it is amazing how poorly calibrated they are with the gas gage. I have not found the gage to read more gas than the tank actually has, but the opposite. It would appear that a 1/4 tank reading on the gas gage is usually more like 3/8 or maybe 1/2. I guess it's better to think you are about out of gas and have a few gallons left than the opposite. This phenomenon may explain why so many think their tank capacity is less than 20 gallons. AND, the photo of the 68 manual that 1968 Baby Blue posted shows "Imperial" gallons as well which may lead a speed reader to the wrong conclusion.

My 72 tank is very near 20 US gallons.

[FirstOwner69]

Originally Posted by '72_GMC

That Gas station near the park gets an extra $1/Gallon, From Washington State, I apologize for his greed. That is the whole point of wanting a larger Tank, that thing only gets about 8MPG and those gas dealers out in the country side can get really opportunistic in charging for fuel

We finally found a gas station on the east side of the park heading downhill (thankfully) on highway 410. Our mileage was not good because we were carrying the cabover camper.

An interesting side note. We also had a 175 cc Honda along. On a side trip to Bumping Lake it also needed gas. We bought it at general store. The "pump" was the old style with a glass cylinder at the top. We hand pumped a gallon into the cylinder then drained it into the bike. When I asked the lady in the store if they had a pay phone, she said, "You're in the country now son" and directed us to the gas station 20 miles away where we'd gassed up the truck. I sure would like to have that gas pump!! I'd never seen one and never saw another.