Factory installed rear gas tank?

[64galaxiemann]

I own a 1970 Chevy longhorn 3/4 ton truck with a gas tank between the frame rails aft of the differential. It appears to be factory installed. The one on my truck is badly pitted and rusted. Does anyone out there have any info on this tank or where I can get one, used or new...Any phone numbers or e-mail address would be appreciated.

[70cst]

As far as I know...this location for a gas tank was never an option for 67-72 Chevy/GMC trucks.

[Longhorn Man]

that is correct. There were some saddle tanks in front of the rear wheels, but not aft.

[roger0080]

Yes that is factory, but only in the year 1970 could could you get the Blazer fuel tank setup in a fleetside pickup as an auxiliary tank. It was "N18 AUXILIARY FUEL TANK" on the spid sticker.

In 1971/1972 they moved the auxiliary fuel tank to the front left of the box that you commonly see.

I would think a Blazer fuel tank would do it.

[mr48chev]

I have one of the "saddle tanks" stashed away but have never seen a tank mounted on the inside of the frame on one of these trucks.
My guess is that someone has installed a tank off another truck of some sort there. If it looks factory they did a pretty decent job of installation.

[70cst]

Originally Posted by roger0080

Yes that is factory, but only in the year 1970 could could you get the Blazer fuel tank setup in a fleetside pickup as an auxiliary tank. It was "N18 AUXILIARY FUEL TANK" on the spid sticker.

In 1971/1972 they moved the auxiliary fuel tank to the front left of the box that you commonly see.

I would think a Blazer fuel tank would do it.

I would love to see that in a SPID because I have never seen any documentation to support this was a factory option. I would almost bet you a years membership to this sight that it was never a factory option. I will go through my 70 Dealers options manual to verify this. By what basis or documented facts are you sayng this was an option for a 1970 truck only? Just curious because there are things that I still do not know about my 70cst and this is new to me. I am always willing to learn and though I feel that I am correct I am always willing to be corrected when I am in error and I just might be wrong with my opinion. Thats why they call this forum the Chevy/GMC Class 101.

[68gmsee]

You've got us interested now. I've never seen a factory rear tank either.

Where is the gas filler located? Look at it very closely to see if it was an add on. Also, is there a tank behind the seat?

I would guess that if it was factory installed the access would be spot welded in and, more than likely, it would be like the blazers or suburbans.

In any case, as was already mentioned, I'd look for a tank from a blazer or suburban of that era if you want to maintain a stock look.

[roger0080]

Oh ye children of little faith...

From the 1970 Truck Dealer Book, January 30, 1970 for C-K20 Options:
"Tank, Auxiliary Fuel: Available on C20 Fleetside Pickup models with side mounted wheel carrier only. Not available when paint stripes or custom upper side moldings are ordered. Includes 20.5 gallon capacity frame mounted tank located between side rails ahead of rear crossmember with floor mounted manual selector valve located next to driver's seat and fuel gauge selector switch located on instrument panel...........N18"

And yes, I do have a photograph of the N18 option on the spid.

If your spid is shot up, the best way to tell if if yours was a factory job or a hack job, remove the rubber neck tank seal from the fender and look at the quality of the hole in the fender. If the hole is smooth and balanced like it was stamped, then it's factory. If it is jagged, rough, rusty, dents, oblong, then it's a saber saw hack job conversion. Since you have a 3/4T then it's even more in your favor.

I've done this conversion and it's tough to get a nice professional hole cut into the fender with all it's curves. Plus it's covered up so it doesn't need to be perfect (especially on a daily driver as it was).

[64galaxiemann]

You guys are great!!! I peeled the filler port seal away and the hole is stamped and rolled in like the one on the cab. There is a selector valve in the cab on the floor and also a switch that I cut off because I thought it was for a old light system of some sort but I did notice that it appeared to have a factory tag on it. Yes I saved it. The trucks spare tank that we are talking about has a area that looks like the spare tire would fit against it. The filler port is on the drivers side Just aft of the rear tire well nd about the same height as the in cab tank and I noticed that the wood bed is cut away for the port lines....Now, how do I get a replacement??? What kind of pickup/suction tube do I use and does anyone have any pictures I can use for reference. My truck also has dual batteries ..Thanks for all the work you guys...Alex

[68gmsee]

Learn something new all the time... I've never seen a stock rear tank on these trucks so I think you're going to have a hard time finding and exact replacement.

If you can find one, you may have to go with a blazer/suburban tank. Not sure if those had the recessed area for the spare tire though.

Good luck.

[Shane]

Originally Posted by 70cst

I would almost bet you a years membership to this sight that it was never a factory option.

You almost owe someone $25.

[thirdstreettito]

Originally Posted by Shane

You owe someone $25.

lmao

[70cst]

Originally Posted by Shane

You almost owe someone $25.

Quote:
Originally Posted by Shane You owe someone $25.

Hey...what happened to the word "Almost"?

Seeee the importance in using the right words..."ALMOST" bet. Geee maybe I should become a politician?

[Longhorn Man]

it's a good thing I didn't bet my normal wager on this one.... a kick in the daddy parts.

[thirdstreettito]

Originally Posted by 70cst

Hey...what happened to the word "Almost"?

Hold on, lemme check my pocket..........HERE IT IS! The little rascal got away from me again. Phew, time for the choke collar!

[70cst]

Originally Posted by thirdstreettito

Hold on, lemme check my pocket..........HERE IT IS! The little rascal got away from me again. Phew, time for the choke collar!

I'm glad you found my "Almost" I was getting a little nervous.

[Longhorn Man]

and now you can go back to being ALMOST a little nervous

[sick69]

Playing the devils advocate here but,,,, any filler around the area? If someone cut that section out of a cab and welded it into the bed it would look factory, but still be an add on. I know there are several people on this board that could weld that in and sand it down to look factory and NOT use any filler on it. Would have to be really carefull and use ALOT of patience but it could be done.



Just a thought.

Frank

[68gmsee]

Originally Posted by sick69

Playing the devils advocate here but,,,, any filler around the area? If someone cut that section out of a cab and welded it into the bed it would look factory, but still be an add on. I know there are several people on this board that could weld that in and sand it down to look factory and NOT use any filler on it. Would have to be really carefull and use ALOT of patience but it could be done. Just a thought. Frank

Already been suggested in prior posts... He looked at the gas filler area and it looks like the stock opening (see post #9). I doubt it could be replicated exactly.

From what I've seen on these old trucks, most factory sheetmetal was either spot welded, crimped, or bolted. I don't see a lot of welded sheetmetal.

[mrein3]

Originally Posted by sick69

Playing the devils advocate here but,,,, any filler around the area? If someone cut that section out of a cab and welded it into the bed it would look factory, but still be an add on. I know there are several people on this board that could weld that in and sand it down to look factory and NOT use any filler on it. Would have to be really carefull and use ALOT of patience but it could be done.

I'm not saying I could weld it in perfectly but I did cut the "hole" out of a junk bed to do just what you suggested. I cut out both the inside hole and outside hole.