How many gallons of gas??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

c10crazy · 07-15-2011, 11:21 PM

I know my gas gauge is not that accurate but how many gallons of gas does our 67-72 trucks hold???

Stricklinator · 07-15-2011, 11:25 PM

Someone can correct me, but I believe the standard tank behind the seat is 21 gallons.

Paul
Posted via Mobile Device

c10crazy · 07-15-2011, 11:30 PM

That was the number that was in my head too! Tonight I was on a quarter tank and I filled it up with 9.5 gallons and the needle is almost a quarter past the full mark! That means when I'm showing a quarter tank it's almost a half tank! Do I have a bad gauge or sending unit???

Fldawg · 07-15-2011, 11:35 PM

behind the seat is 16 gallons, the aftermarket tanks that go between the frame rails are 20

elf w/capital T · 07-15-2011, 11:54 PM

i was under the assumption having the suicide tank was only 21 gal.... hmm i never even realized because i dont ever fill her up.

1968CHEVYC10 · 07-15-2011, 11:54 PM

I've heard 20 for 1/2 tons and 21 for 3/4 ton+, I just filled mine from empty took 20 gal.

Stricklinator · 07-16-2011, 12:07 AM

In the LMC catalog, the replacement tank behind the seat is 20 gallons and the Blazer tank is 21 gallons.

Paul
Posted via Mobile Device

Lee H · 07-16-2011, 04:45 AM

My 72 owners manual says 20 gallon capacity.
Posted via Mobile Device

**special-K** · 07-16-2011, 05:49 AM

21 gallons. I've had them take over 20 gallons.

**Stocker** · 07-16-2011, 10:28 AM

Tanks behind the seats apparently came in two different sizes... I believe 20+ gallon was most common.

c10crazy · 07-16-2011, 11:07 AM

Thanks for all the replies. I can't find my service manual that's why I posted. Now I have to determine if my gas gauge is the problem or my fuel sending unit. I'm guessing since they are both technically working (just not accurate) it's the gauge?

**leddzepp** · 07-16-2011, 11:21 AM

Quote:

Originally Posted by c10crazy

I can't find my service manual

I know somebody here who has one

**70STOVEBOLT** · 07-16-2011, 11:47 AM

I can fit a little over 20 in mine from bone dry, but that is filling the neck also. I know, you're not supposed to do that since the cap is not vented, but when you get 14-15 mpg you want all the capacity you can get!!

**Stocker** · 07-16-2011, 12:30 PM

Quote:

Originally Posted by leddzepp

I know somebody here who has one

1972RedNeck · 07-16-2011, 04:44 PM

Quote:

Originally Posted by Lee H

My 72 owners manual says 20 gallon capacity.
Posted via Mobile Device

Quote:

Originally Posted by 70STOVEBOLT

I can fit a little over 20 in mine from bone dry, but that is filling the neck also. I know, you're not supposed to do that since the cap is not vented, but when you get 14-15 mpg you want all the capacity you can get!!

Try 8.2 MPG. That's the highest I have got with my 383 so far. It likes to

though.

dmack91 · 07-16-2011, 05:14 PM

Quote:

Originally Posted by c10crazy

Thanks for all the replies. I can't find my service manual that's why I posted. Now I have to determine if my gas gauge is the problem or my fuel sending unit. I'm guessing since they are both technically working (just not accurate) it's the gauge?

What does your gauge read now? If it is at 3 o'clock and stuck there, try grounding the sending unit post to a good ground. If the gauge goes to 9 o'clock, it is the sending unit that is bad. If the sender is working, the resistance should read between 0-90 ohms from the post to ground. Also make sure the wire from the sending unit post goes to the terminal on the fuse block that it is supposed to.

Mine turned out to be a bad sending unit - $30 later all was well.

stroked69 · 07-16-2011, 06:02 PM

pull the carpet sill on the drivers side and check the wire. I have found that it typically goes bad in this area.

**70STOVEBOLT** · 07-18-2011, 08:40 AM

What if it goes to about 2 o'clock when it is full and hits empty when it's got about a quarter of a tank left? Is there any way to "calibrate" the gauge? Mine works fine other than it seems to be off.

Murphy IRE · 07-18-2011, 02:36 PM

Again, 20 plus, but you are into the neck and it will slosh out. I have two saddle tanks two: one at 19 and the other around 12 gallons. With my 400, I would love to get 14 MPG. After all the carb work, I think I'm at 11 MPG and that's being easy on the pedal. Neither saddle tank is connected to the gauge. I run them out first and then switch to the main tank.

AirSpeed · 07-18-2011, 05:34 PM

Quote:

Originally Posted by 70STOVEBOLT

What if it goes to about 2 o'clock when it is full and hits empty when it's got about a quarter of a tank left? Is there any way to "calibrate" the gauge? Mine works fine other than it seems to be off.

You may have a leak in the brass float, it is probably half full gas and won't float to the top. Pull the sender out of the tank, it's held in with a lock ring. My 69 was doing the same thing, I went to the local NAPA parts store to get a new float and they had one in stock. The brass float simply clips into the float lever, easy fix!
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stsalvage · 07-18-2011, 06:32 PM

well when gas was 1.00 a gallon back many moons ago back in 1989 my 1965 3/4 ton truck I could only get 16.00 into my tank so that mean's i have a 16 gallon tank and with a 350 with a 2 speed power glide with 4;10 gears running 235-85-16 tire's motor home 10 ply radials when there new I get 14 MPG with a 290 HP engine crate engine i run the smaller tires the 9.50 I can't get over 55 Mph with out it revving up past 4000 RPM's But buy running the 235-85-16 tall tire By 2 inches taller I changed my gearing by 377 But the power glide dose not help cus its a 2 speed But only had the power glide out 2 times do to seals and i have over 2 million Miles on the truck.From 1991 i put over 890K miles on this truck before that it use to be a long haul truck for UCR collage orange groves In Calif more of less SUNKIST oranges

07-15-2011, 11:21 PM	#1
c10crazy Like a Rock! Join Date: May 2002 Location: USA Posts: 1,092	How many gallons of gas??? I know my gas gauge is not that accurate but how many gallons of gas does our 67-72 trucks hold??? __________________ 69 LWB Runs great - work in progress Mess with me and you mess with the whole trailer park!

07-15-2011, 11:25 PM	#2
Stricklinator Registered User Join Date: Feb 2011 Location: Murrieta, California Posts: 234	Re: How many gallons of gas??? Someone can correct me, but I believe the standard tank behind the seat is 21 gallons. Paul Posted via Mobile Device __________________ 1969 C/20, 307, 4-speed, rusty with manual steering and brakes!

07-15-2011, 11:30 PM	#3
c10crazy Like a Rock! Join Date: May 2002 Location: USA Posts: 1,092	Re: How many gallons of gas??? That was the number that was in my head too! Tonight I was on a quarter tank and I filled it up with 9.5 gallons and the needle is almost a quarter past the full mark! That means when I'm showing a quarter tank it's almost a half tank! Do I have a bad gauge or sending unit??? __________________ 69 LWB Runs great - work in progress Mess with me and you mess with the whole trailer park!

07-15-2011, 11:35 PM	#4
Fldawg Registered User Join Date: Jan 2011 Location: Lynn Haven Florida Posts: 1,019	Re: How many gallons of gas??? behind the seat is 16 gallons, the aftermarket tanks that go between the frame rails are 20 Last edited by Fldawg; 07-15-2011 at 11:37 PM. Reason: forgot

07-15-2011, 11:54 PM	#5
elf w/capital T Registered User Join Date: Feb 2011 Location: North Carolina Posts: 994	Re: How many gallons of gas??? i was under the assumption having the suicide tank was only 21 gal.... hmm i never even realized because i dont ever fill her up. Last edited by elf w/capital T; 07-15-2011 at 11:54 PM. Reason: i was reading the post before me :hammer:

07-15-2011, 11:54 PM	#6
1968CHEVYC10 Registered User Join Date: Aug 2009 Location: Tomball, TX Posts: 578	Re: How many gallons of gas??? I've heard 20 for 1/2 tons and 21 for 3/4 ton+, I just filled mine from empty took 20 gal. __________________ '68 C10 LWB 6.2NA/NP833 3.73's

07-16-2011, 12:07 AM	#7
Stricklinator Registered User Join Date: Feb 2011 Location: Murrieta, California Posts: 234	Re: How many gallons of gas??? In the LMC catalog, the replacement tank behind the seat is 20 gallons and the Blazer tank is 21 gallons. Paul Posted via Mobile Device __________________ 1969 C/20, 307, 4-speed, rusty with manual steering and brakes!

07-16-2011, 04:45 AM	#8
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,147	Re: How many gallons of gas??? My 72 owners manual says 20 gallon capacity. Posted via Mobile Device __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

07-16-2011, 05:49 AM	#9
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: How many gallons of gas??? 21 gallons. I've had them take over 20 gallons. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 07-16-2011 at 06:04 AM.

07-16-2011, 10:28 AM	#10
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,722	Re: How many gallons of gas??? Tanks behind the seats apparently came in two different sizes... I believe 20+ gallon was most common. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

07-16-2011, 11:07 AM	#11
c10crazy Like a Rock! Join Date: May 2002 Location: USA Posts: 1,092	Re: How many gallons of gas??? Thanks for all the replies. I can't find my service manual that's why I posted. Now I have to determine if my gas gauge is the problem or my fuel sending unit. I'm guessing since they are both technically working (just not accurate) it's the gauge? __________________ 69 LWB Runs great - work in progress Mess with me and you mess with the whole trailer park!

07-16-2011, 11:47 AM	#13
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,414	Re: How many gallons of gas??? I can fit a little over 20 in mine from bone dry, but that is filling the neck also. I know, you're not supposed to do that since the cap is not vented, but when you get 14-15 mpg you want all the capacity you can get!! __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear

07-16-2011, 06:02 PM	#17
stroked69 Registered User Join Date: Jul 2011 Location: Idaho Posts: 22	Re: How many gallons of gas??? pull the carpet sill on the drivers side and check the wire. I have found that it typically goes bad in this area.

07-18-2011, 08:40 AM	#18
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,414	Re: How many gallons of gas??? What if it goes to about 2 o'clock when it is full and hits empty when it's got about a quarter of a tank left? Is there any way to "calibrate" the gauge? Mine works fine other than it seems to be off. __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear

07-18-2011, 02:36 PM	#19
Murphy IRE Registered User Join Date: Oct 2009 Location: South Denver Metro, CO Posts: 385	Re: How many gallons of gas??? Again, 20 plus, but you are into the neck and it will slosh out. I have two saddle tanks two: one at 19 and the other around 12 gallons. With my 400, I would love to get 14 MPG. After all the carb work, I think I'm at 11 MPG and that's being easy on the pedal. Neither saddle tank is connected to the gauge. I run them out first and then switch to the main tank.



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07-18-2011, 06:32 PM	#21
stsalvage Scrapper 1 Join Date: Jan 2007 Location: Riverside Calif Posts: 1,649	Re: How many gallons of gas??? well when gas was 1.00 a gallon back many moons ago back in 1989 my 1965 3/4 ton truck I could only get 16.00 into my tank so that mean's i have a 16 gallon tank and with a 350 with a 2 speed power glide with 4;10 gears running 235-85-16 tire's motor home 10 ply radials when there new I get 14 MPG with a 290 HP engine crate engine i run the smaller tires the 9.50 I can't get over 55 Mph with out it revving up past 4000 RPM's But buy running the 235-85-16 tall tire By 2 inches taller I changed my gearing by 377 But the power glide dose not help cus its a 2 speed But only had the power glide out 2 times do to seals and i have over 2 million Miles on the truck.From 1991 i put over 890K miles on this truck before that it use to be a long haul truck for UCR collage orange groves In Calif more of less SUNKIST oranges

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