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#1 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,290
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Actual Capacity of K/5 Belly Tank?
Anyone know the actual capacity of the stock gas tank in a '71 GMC Jimmy?
Owners' Manual states a nominal 20.5 US Gallons. Last Weds evening, I ran out of gas. [My fuel gauge doesn't function. I know the gauge itself is good, so it must be in the sender. The belly tank is protected by a huge skid plate held on by about 48 capscrews, with the authority of 52 years of rust-in-place. I usually use a log. But it's not infallable]. Roadside Rescue dispatched a driver, who told me he needed a dollar amount, for the gas, so I said get me $20 worth. At $3.599 that should have bought 5.55 gallons. He showed up with a plastic 5 gallon gas jug and funneled it into my tank. I gave him a Twenty. Truck started and I got to my meeting, 45 minutes late. After the meeting, [about 3 - 5 miles later] I stopped at a station and pumped gas until it shut off from filling. I did not overfill or spill. Gas Pump registered 19.5 gallons. So the math is off. I know I did not burn 4.5 gallons in 5 miles. 5+ 19.5= 24.5, which is beyond the capacity of the Blazer tank. What happenned to 4 gallons?
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Every 25 years I like to rebuild that 292, whether it needs it or not. |
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#2 |
All stock and staying that way
![]() Join Date: Jul 2003
Location: Elkland, PA
Posts: 1,508
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At least in 1970, the capacity was advertised as 23.5 US gallons. Pretty sure it's the same 1969-72.
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1970 K/5 Blazer CST 4WD, Bronze, 93k ACT. miles, 350, 4 speed, positraction, 16.5" x 8.25" wheel option, tilt, tach, vacuum, AM/FM, manual throttle...Dad ordered and purchased new 4/70. Currently frame off restoration in progress... ![]() 1972 Cheyenne Super 20 2WD, DK Blue/White, 90K ACT. miles, 402, TH400, 4.10 open, tilt, tach, vacuum, A/C, AM/FM, manual throttle.. A mostly original paint never rusted Texas survivor... ![]() 2017 Sierra 1500 SLT 4WD, Black, 41k miles, 5.3, 6L80E, 3.42 LS, 20" polished wheels, everything but moonroof and 6.2... 2019 Canyon SLT 4WD, White, 60k miles, 3.6, 8L45, 3.23 LS, 18" wheels |
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#3 |
Senior Member
![]() Join Date: Dec 2009
Location: TN.
Posts: 8,181
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Re: Actual Capacity of K/5 Belly Tank?
The information I found was 23.5 gallons also.
And also: Was that 5 Gallon Gas Jug Full ??? Year:: 1970 Base Price: 2,955 (6 cid.) 3,050 (8 cid.) Wheel Base: 104 in. Length: 177.5 in. Std. Engine, (net HP): OHV Six-cylinder 250 cid. (110) @ 4000 rpm Rear Axle: GM Corporate 12-bolt (8.7/8-in. 1.31 Axle Dia. 30 Spline) Transmission (M): SM318/SM326/SM330/T-89A/T-150 3 spd. (2.47-3.50:1 First Gear) SM465 4 spd. (6.55:1 First Gear) Transfer Case (M): NP205 (1.96:1 Low Range) Dana 20 (2.03:1 Low Range) Production Total: 11,527 Weight: 3,677 (6 cid.) 3,807 (8 cid.) Fuel Tank Capacity: 23.5-gallon Height: 68.7 in. Opt. Engine, (net HP): OHV Six-cylinder 292 cid. (125) @ 3600 rpm OHV Eight-cylinder 307 cid. (135) @ 4000 rpm OHV Eight-cylinder 350 cid. (170) @ 3600 rpm Front Axle: Dana 44 (8.5-in. 1.31 Axle Dia. 30 Spline) Transmission (A): TH350 (2.52:1 First Gear) Transfer Case (A): NP205 (1.96:1 Low Range) Notes: New grill with six groups of silver "dashes" above and below the horizontal aluminum center bar with Chevy's name across it. The Blazer's single-unit body was joined to a heavy channel steel frame and had a completely removable fiberglass top. A 4x2 Blazer was produced this year, but less than 1,000 were made.
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________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build |
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#4 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,290
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Re: Actual Capacity of K/5 Belly Tank?
OK. 23.5 gallons. That is a big difference of three gallons more.
The gas jug the guy had was a Wedco, not the Blitz style copy of the US GI can or the WWII German-inspired NATO 20L jerry can. I've had a few, and it looked pretty full. Not sure if he had the proper caps on both ends, so some may have sloshed out on the way. I guess it was close enough for gov't work, so I didn't get boned,,, Much. For an emergency I did OK. Thanks, guys. I was under the impression the Blazer belly tank held less than the Behind-the-Seat tank. I've crammed 22.5 into the one in my '68 C/10 Stepside, although the manual states 20 gallons. Also I've never seen a Factory-optioned [RPO L25] 292 L6 in a Blazer/Jimmy. I see it was an option, but apparently a very rare one.
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Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 11-13-2023 at 02:50 AM. |
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#5 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,290
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Re: Actual Capacity of K/5 Belly Tank?
Funny, though. LMC Catalog lists the Blazer/Suburban tank as 21 Gallons.
Conversion belly tanks for under pickups are 17 Gallons. And Truck and Car Shop calls theirs a 20 Gallon tank... Pretty sure mine's an original.
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Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 11-13-2023 at 02:51 AM. |
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#6 |
Senior Member
![]() Join Date: Dec 2009
Location: TN.
Posts: 8,181
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Re: Actual Capacity of K/5 Belly Tank?
I noticed that Some of the vendors, when searching for capacity,
Was different. I had a 76 Blazer that had a 31-gallon tank. This is what sparked my curiosity. The only true way too tell what yours holds (you Know), Run it out of gas and have a (measured amount to add back).
__________________
________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build |
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