Increasing Fuel Capacity

[septantrionalis]

I have a 1974 Chevy K10 with a single ~14 gallon fuel tank under the passenger side.  With the gas mileage I get, I am filling up every other day.  I'd like to expand it.  As of current, I can think of two options.  The first would be to add the second tank under the driver side and get that working with the switch, etc.  I know this was an option back in the day.  The problem is that my bed only has one fuel cap, so I'd have to figure out how to fill up that second tank.  Not sure how hard this would be.

The other option would be to just add an auxiliary fuel tank in the bed that's gravity fed.  Bed space isn't too important for me since I have another truck that can be used for hauling.  Has anyone put a fuel tank in the bed?  Are there any recommendations of one method over the other or maybe another option?

[Irish_Alley]

you could add a second tank to the other side then have a pipe connect the two together and only have a vent for it. then fill your old one up and it will also transfer to the other side. the issue with gravity fed is if will equal its level so if you dont have a way to shut the fuel down 100% then it might just pour into the carb then into the engine or other tank. i know with my 79 i was at one point getting 7 or so mpg changed tires to a narrower set and it went to 10. but even then i had to fill up every other day or 3 days with a 20 gal tank

[septantrionalis]

You know, Tim, thats not a bad idea.  I didn't realize that I could install the second tank and just connect the two.  I may just go that direction.

[Irish_Alley]

if i was to do it i would have some type of valve plumbed in on each tank so if you get a leak or something you can shut them both down. and have it so its not just sitting there but protected a little.

[82silverado]

If it was mine I would change the bed and put in a factory dual tank.

[zieg85]

My uncle installed a second tank on my 85 using the pre-gas door tank and filler neck, just used a hole saw.  The neck stuck out a little but looked fine.  One problem I had is it wouldn't pass the emission test for a sealed gas cap but they accepted my explanation that the tank was empty and not being used (which was the truth)

[VileZambonie]

Add a 30 gal blazer tank

[75gmck25]

Adding the 2nd saddle tank was a common dealer-installed option, and they just cut a hole in the bed that matched the other side.  It may be a little hard to find the original solenoid that mounts under the bed, but they are still available.  If your fuel pump only has two ports (in and out) its easier to find the solenoid, but if you have a third line on the pump for a fuel return you need a 6 port solenoid.

If you add a Blazer tank in the rear you need to remove the spare tire and brackets, and install the filler tube up into the corner of the bed.

Bruce

[hatzie]

Adding the 2nd saddle tank was a common dealer-installed option, and they just cut a hole in the bed that matched the other side.  It may be a little hard to find the original solenoid that mounts under the bed, but they are still available.  If your fuel pump only has two ports (in and out) its easier to find the solenoid, but if you have a third line on the pump for a fuel return you need a 6 port solenoid.

If you add a Blazer tank in the rear you need to remove the spare tire and brackets, and install the filler tube up into the corner of the bed.

Bruce

If the truck didn't have the NL2 Auxilliary fuel tank option from GM it's easier to install the 1981-1991 motorized valve than it is to try to source a 6 port solenoid valve. 

You could put the blazer fuel fill behind the license plate just like 1960's to 1980's cars.

[roundhouse]

Can probably put the fill tube inside the wheel well above and in front where the tire won't rub it


Sent from my iPhone using Tapatalk

[Captkaos]

You really need to put the filler in the bedside.  When I was younger I tried the fill in the wheelwell.  That was a pain.  Probably not as bad as a 2WD.

Blazer fill had to be above the bed floor unless you REALLY want it to hang low.

Factory tank should be 16 gallon.  I would use the 81-up switch valve and a second tank, Or the Blazer tank in the back.

Chris Lucas
73-87chevytrucks.com
squarebody.biz

[VileZambonie]

I've seen guys put the filler behind the taillight so that it is hinged.

[Captkaos]

That is a lot of fab work.  I just ran mine in the bedside.  Moved it to the back.

Chris Lucas
73-87chevytrucks.com
squarebody.biz