Larger fuel tank capacity - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Crusty69 · 09-07-2022, 10:50 AM

Forgive me if this has been covered already but I searched and couldn't find much. Obviously these trucks don't get good mileage in any capacity, but, has anybody swapped in a larger tank for better fuel range so you can make it farther between fill ups? I want to get the tank out of the cab anyway so I'm looking for the largest tank I can fit under the bed.

I saw someone once using a 70s f body tank and they mounted it so it filled behind the license plate which would be a nice setup. Those tanks are 21 gallons which would give me 5 additional gallons. I'll go this route if it's the biggest thing I can find, but I'd love to get something 28-30 gallons if it's possible. Space may be an issue.

**Palf70Step** · 09-07-2022, 10:55 AM

I plan on putting in a 31 gallon square-body suburban tank in my 70 (LWB). They also make one that is 40ish gallons. The standard square-body Blazer/Suburban tank is 25 gallons if yours is lower a good bit. You will have to make a custom filler for the tank. Either behind taillights, sidemaker or inside bed corner.

Here is one of the videos I was referencing.

https://www.youtube.com/watch?v=2e-J_0_djjE

It is for 4x4, but should work on the 2WD model

Here is another from an older board member

https://67-72chevytrucks.com/vboard/...d.php?t=218898

The attachment is another one I save from somewhere many years ago.

**67 twins** · 09-07-2022, 12:14 PM

The in cab tank is 21 gallons, so you don't gain anything with that fbody tank.

Crusty69 · 09-07-2022, 02:22 PM

Quote:

Originally Posted by 67 twins

The in cab tank is 21 gallons, so you don't gain anything with that fbody tank.

From what I understand, some are 16 and some are 21. If I could fit 21 gallons in, I probably wouldn't worry about it.

**Sheepdip** · 09-07-2022, 03:18 PM

Quote:

Originally Posted by Crusty69

From what I understand, some are 16 and some are 21. If I could fit 21 gallons in, I probably wouldn't worry about it.

The SWB add on saddle tanks were 16 gallons, behind the seat factory was 21 gallons.

**Stocker** · 09-07-2022, 04:15 PM

Quote:

Originally Posted by Sheepdip

The SWB add on saddle tanks were 16 gallons, behind the seat factory was 21 gallons.

Same as my K20. One time years ago on a cross-country trip it took just over 50 gallons to fill the tanks.

09-07-2022, 10:50 AM	#1
Crusty69 Registered User Join Date: Mar 2022 Location: ky Posts: 17	Larger fuel tank capacity Forgive me if this has been covered already but I searched and couldn't find much. Obviously these trucks don't get good mileage in any capacity, but, has anybody swapped in a larger tank for better fuel range so you can make it farther between fill ups? I want to get the tank out of the cab anyway so I'm looking for the largest tank I can fit under the bed. I saw someone once using a 70s f body tank and they mounted it so it filled behind the license plate which would be a nice setup. Those tanks are 21 gallons which would give me 5 additional gallons. I'll go this route if it's the biggest thing I can find, but I'd love to get something 28-30 gallons if it's possible. Space may be an issue.

09-07-2022, 12:14 PM	#3
67 twins Senior Member Join Date: Mar 2019 Location: Herculaneum MO (20 minutes south of St. Louis Posts: 588	Re: Larger fuel tank capacity The in cab tank is 21 gallons, so you don't gain anything with that fbody tank. __________________ 67 C10 283 T5 swapped longbed fleetside = wife's daily driver 67 C20 292 (originally a 250)4speed longbed fleetside w/original wooden bed=my project truck 67 C10 283+.060 (so a 292 as well)T5 swapped longbed fleetside=my DD 72 C1500 Sierra Grande 350 TH350 longbed fleetside=wife's fair weather truck Can you tell we are fans of longbed fleetsides & 67s Chris



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