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

Roper · 05-01-2007, 12:27 PM

My 81 full size long wheelbase truck has two 16 gallon tanks mounted on each side of the truck.
Im thinking about replaceing them with factory 20 gallon tanks.
My question is are the 20 gallon tanks a direct bolt on. Will the hangers on the frame have to be moved to make the tank straps line up.
I guess I will need shorter filler hoses but besides this is it basically I straight bolt on job without modifications?
Also I havnt taken my old tanks off yet but everything looks rusty. I know im going to need new tank straps and rubbers but im wondering what else im going to end up replaceing. Example lock ring and o ring for the sending units?
Thanks

Srubydo1986 · 05-01-2007, 02:42 PM

I have the same setup. I was wondering the same maybe someone will chime in and answer this. But i do think it just a bolt in cause from my truck to mu other with the 20 gal looks the same.

78Chevy · 05-01-2007, 06:23 PM

I'm no expert by any means, but I think that it would be easy to change from a 16 gal to a 20 gal if you have a long wheel base. We have two long wheel base truck, both with dual tanks and they are 20 gal. I don't believe that it would work on a short wheel base. I wish it would though!

Al

Srubydo1986 · 05-01-2007, 06:46 PM

mine a long bed with 2 16 gal tanks

gchemist · 05-01-2007, 07:34 PM

Why don't you install a 45 gallon tank?

Srubydo1986 · 05-01-2007, 08:00 PM

me to lazy him probley like the sattle bag setup.

Roper · 05-02-2007, 10:46 AM

Quote:

Originally Posted by gchemist

Why don't you install a 45 gallon tank?

I have dual exhausts because my truck is lifted <front driveshaft>and the dual exhaust would be in the way.
Thanks everyone

SanitysBane · 05-02-2007, 10:07 PM

If you have a long bed, a 20 gallon tank will bolt right in.

Roper · 05-03-2007, 09:36 PM

Well I went into town today to buy some parts. Got talking to the mechanic at the GM dealership. He said he put the larger tanks on his own 81 long box years ago. Said he cant remember all the details except it was a pain.
#1 He said that unless you have the box off the truck itas a real pain. Example unhooking up the wires to the sending unit.
#2 He said with the longer tanks the frame brackets are in the wrong spot. He couldnt remember if he had to just move the back brackets or get replacement ones for a 20 gallon tank.
On the plus side he said the frames are all drilled for the new bracket location.
Anyway im thinking the heck with it. Im going to put a flat deck on my truck anyways.
Right now I have a huge third tank in my bed but its not DOT approved and it doesnt have a fuel gauge. I noticed in the parts store that they have bed tanks<probable 60 gallon> that are diamond alunimun and DOT approved for gas. These tanks mount right in the bed of your truck. Im thinking when put the deckl on my truck I will buy one of these bed tanks and then take off my factory tanks.
With the factory tanks gone I can build custom running boards that I can bolt directly to the frame <think strong>and those old fuel tanks wont be in the way.

SanitysBane · 05-03-2007, 10:28 PM

You don't have to get new brackets, I went from a 16 gallon tank to a 20 gallon tank on my '83 long bed and all I needed was a 20 gallon tank and the filler hose.

Roper · 05-04-2007, 10:02 AM

Quote:

Originally Posted by SanitysBane

You don't have to get new brackets, I went from a 16 gallon tank to a 20 gallon tank on my '83 long bed and all I needed was a 20 gallon tank and the filler hose.

Did you have to move the back bracket? Thanks.

05-01-2007, 06:23 PM	#3
78Chevy Registered User Join Date: Nov 2006 Location: Malvern, AR Posts: 80	Re: Larger fuel tanks I'm no expert by any means, but I think that it would be easy to change from a 16 gal to a 20 gal if you have a long wheel base. We have two long wheel base truck, both with dual tanks and they are 20 gal. I don't believe that it would work on a short wheel base. I wish it would though! Al __________________ _____________________________________________ 97 K1500 Tahoe 5.7 Stock "Driver" 78 swb C10 Silverodo/ 350cu. dual Flowmaster's, MSD cap, and wires. "Project" LONG LIVE AMERICA!!

05-01-2007, 06:46 PM	#4
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Larger fuel tanks mine a long bed with 2 16 gal tanks __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) 1970 chevelle 2dr sedan Latest update June 24 2007. *1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one

05-01-2007, 07:34 PM	#5
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Larger fuel tanks Why don't you install a 45 gallon tank? __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

05-01-2007, 08:00 PM	#6
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Larger fuel tanks me to lazy him probley like the sattle bag setup. __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) 1970 chevelle 2dr sedan Latest update June 24 2007. *1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one

05-02-2007, 10:07 PM	#8
SanitysBane Registered User Join Date: May 2004 Location: Lubbock, Texas Posts: 2,121	Re: Larger fuel tanks If you have a long bed, a 20 gallon tank will bolt right in. __________________ '96 Nissan Pathfinder '02 Firebird Trans Am. '88 K5 Blazer

05-01-2007, 12:27 PM	#1
Roper Registered User Join Date: Feb 2005 Location: Alberta Posts: 248	Larger fuel tanks My 81 full size long wheelbase truck has two 16 gallon tanks mounted on each side of the truck. Im thinking about replaceing them with factory 20 gallon tanks. My question is are the 20 gallon tanks a direct bolt on. Will the hangers on the frame have to be moved to make the tank straps line up. I guess I will need shorter filler hoses but besides this is it basically I straight bolt on job without modifications? Also I havnt taken my old tanks off yet but everything looks rusty. I know im going to need new tank straps and rubbers but im wondering what else im going to end up replaceing. Example lock ring and o ring for the sending units? Thanks

05-01-2007, 02:42 PM	#2
Srubydo1986 The Crazy Machanic Join Date: Jan 2007 Location: Nokesville Va Posts: 1,437	Re: Larger fuel tanks I have the same setup. I was wondering the same maybe someone will chime in and answer this. But i do think it just a bolt in cause from my truck to mu other with the 20 gal looks the same. __________________ 1986 Sliverado longbed 400 small block mean as hell, 700r4 trans (5 speed coming one day) 1970 chevelle 2dr sedan Latest update June 24 2007. *1957 4 door stationwagon - pink all original needing a good restore (body great, floors bad) newest additions 1965 shortbed fleet great granddads. Been told im nuts to bring it back from the dead (still going to happen) plans-all stock with a turbo 292 inline 3 speed column shift. and thats it big block 427 and 5 speed trans and ford 9 inch theyhave no home yet thinking what to put them in and a 79 c60 trash truck um no idea i have one

05-03-2007, 09:36 PM	#9
Roper Registered User Join Date: Feb 2005 Location: Alberta Posts: 248	Re: Larger fuel tanks Well I went into town today to buy some parts. Got talking to the mechanic at the GM dealership. He said he put the larger tanks on his own 81 long box years ago. Said he cant remember all the details except it was a pain. #1 He said that unless you have the box off the truck itas a real pain. Example unhooking up the wires to the sending unit. #2 He said with the longer tanks the frame brackets are in the wrong spot. He couldnt remember if he had to just move the back brackets or get replacement ones for a 20 gallon tank. On the plus side he said the frames are all drilled for the new bracket location. Anyway im thinking the heck with it. Im going to put a flat deck on my truck anyways. Right now I have a huge third tank in my bed but its not DOT approved and it doesnt have a fuel gauge. I noticed in the parts store that they have bed tanks<probable 60 gallon> that are diamond alunimun and DOT approved for gas. These tanks mount right in the bed of your truck. Im thinking when put the deckl on my truck I will buy one of these bed tanks and then take off my factory tanks. With the factory tanks gone I can build custom running boards that I can bolt directly to the frame <think strong>and those old fuel tanks wont be in the way.

05-03-2007, 10:28 PM	#10
SanitysBane Registered User Join Date: May 2004 Location: Lubbock, Texas Posts: 2,121	Re: Larger fuel tanks You don't have to get new brackets, I went from a 16 gallon tank to a 20 gallon tank on my '83 long bed and all I needed was a 20 gallon tank and the filler hose. __________________ '96 Nissan Pathfinder '02 Firebird Trans Am. '88 K5 Blazer

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