early/late tank differences - The 1947 - Present Chevrolet & GMC Truck Message Board Network

3QTRTONS · 02-06-2014, 09:05 PM

I was looking to sell my left & right tanks off my '74 C20 to a buddy who has an '87, but looking at LMC and Classic catalogs, there are different stocking #s for 73-80, 81-86, and 87-91. I figured that 87-91 being injected could have a different setup, but what would be the difference between 73/80 & 81-86?

pontgta · 02-06-2014, 09:10 PM

Quote:

Originally Posted by 3QTRTONS

I was looking to sell my left & right tanks off my '74 C20 to a buddy who has an '87, but looking at LMC and Classic catalogs, there are different stocking #s for 73-80, 81-86, and 87-91. I figured that 87-91 being injected could have a different setup, but what would be the difference between 73/80 & 81-86?

Yes 87 has. Baffles inside the tank... It's the only difference

buddy_1 · 02-06-2014, 11:10 PM

The hose fittings were different diameters between my 78 and 85 tanks. The 78 was set up with the old style leaded fuel filler necks and the tanks had larger fittings.

**Captkaos** · 02-06-2014, 11:15 PM

The opening size of the filler hole is different on the 73-81 vs. the 82-91

3QTRTONS · 02-07-2014, 06:52 AM

So I could use these tanks on a later truck if I used "period correct" filler necks/hoses? Would an early filler neck both right up to the later bedside?

Tx Firefighter · 02-07-2014, 07:45 AM

Piecing together fuel fillers can be a real chore. Parts are hard to find and expensive when you do. When I was building my 78 stepside, I tried to use a freebie 87 model tank. After a bunch of effort to figure out a filler setup due to the different size hoses, I found it cheaper to just buy a new tank of the right vintage. It was under 100 bucks delivered.

**Captkaos** · 02-07-2014, 08:16 AM

Realistically the answer is no as TX_Firefighter said.
The tanks require the associated parts. The filler neck on the early versions mount differently to the bed.
If the filers were from a truck with gas doors they would work. If the filler mounted to the bed with a cap they won't. (Barring modifying them)

Your41Plague12 · 02-10-2014, 07:27 PM

The early tanks had a smaller inlet on the tank. I know because I acquired one for my 83 build and it wouldn't work. It's still sitting in my garage at home!

02-06-2014, 09:05 PM	#1
3QTRTONS Registered User Join Date: Mar 2010 Location: Warren, ME. Posts: 235	early/late tank differences I was looking to sell my left & right tanks off my '74 C20 to a buddy who has an '87, but looking at LMC and Classic catalogs, there are different stocking #s for 73-80, 81-86, and 87-91. I figured that 87-91 being injected could have a different setup, but what would be the difference between 73/80 & 81-86? __________________ 1969 ES5500 B E A S T 1976 K20 Suburban 1983 C10 'farm truck' 1984 K10 Suburban 1988 V30 Fire Truck 1941 Dodge WC18 Ambulance 2000 GMC Bus (parts warehouse)

02-06-2014, 11:10 PM	#3
buddy_1 Registered User Join Date: Dec 2013 Location: Humble, Texas Posts: 185	Re: early/late tank differences The hose fittings were different diameters between my 78 and 85 tanks. The 78 was set up with the old style leaded fuel filler necks and the tanks had larger fittings. __________________ I know the "VOICES" aren't real but they have some great ideas. 1978 GMC Sierra Classic C25 1983 Datsun 280ZX Turbo 1997 Chevy Cheyenne K2500 1999 Polaris Sport 400

02-06-2014, 11:15 PM	#4
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: early/late tank differences The opening size of the filler hole is different on the 73-81 vs. the 82-91 __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

02-07-2014, 06:52 AM	#5
3QTRTONS Registered User Join Date: Mar 2010 Location: Warren, ME. Posts: 235	Re: early/late tank differences So I could use these tanks on a later truck if I used "period correct" filler necks/hoses? Would an early filler neck both right up to the later bedside? __________________ 1969 ES5500 B E A S T 1976 K20 Suburban 1983 C10 'farm truck' 1984 K10 Suburban 1988 V30 Fire Truck 1941 Dodge WC18 Ambulance 2000 GMC Bus (parts warehouse)

02-07-2014, 07:45 AM	#6
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: early/late tank differences Piecing together fuel fillers can be a real chore. Parts are hard to find and expensive when you do. When I was building my 78 stepside, I tried to use a freebie 87 model tank. After a bunch of effort to figure out a filler setup due to the different size hoses, I found it cheaper to just buy a new tank of the right vintage. It was under 100 bucks delivered. __________________ I'm on the Instagram- @Gearhead_Kevin

02-07-2014, 08:16 AM	#7
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: early/late tank differences Realistically the answer is no as TX_Firefighter said. The tanks require the associated parts. The filler neck on the early versions mount differently to the bed. If the filers were from a truck with gas doors they would work. If the filler mounted to the bed with a cap they won't. (Barring modifying them) __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

02-10-2014, 07:27 PM	#8
Your41Plague12 Registered User Join Date: Dec 2010 Location: Pittsburgh, PA Posts: 1,009	Re: early/late tank differences The early tanks had a smaller inlet on the tank. I know because I acquired one for my 83 build and it wouldn't work. It's still sitting in my garage at home! __________________ Steve Member of the Foot Pedal Club '83 Chevy K20: 6" Rough Country, 3" Performance Accessories BL, Bushwacker Cutouts, 38x15.50 Mickey Thompson Baja Claws, 350 HP 350 crate engine from Jegs, Turbo 400

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