40 gallon tank into a longbed

[mannyb.]

So i finally got it done. It was a lot more labor intesive than i thought, at least compared to what ive seen on the 70's series trucks. This is the finished shot i just took at work. ill try to upload some of the project shots off my cell phone

[Clyde65]

why did you go 40Gal? how low are you in the rear as far as drop? what is it from?

[jimmydean]

Holy crap! I was looking at putting in a 16 gallon and thought it might be too big.

[mannyb.]

40 gallon out of an 87 burb. "5 drop from cpp. i didnt know it was a 40 gallon when i got it. but i read up on it some here and from captain kaos. little did i know, that its a little bit harder with the trailing arm setup. and i figured, maybe ill fill all the way up once, and then treat it like its only a 20 gallon and never go past half. keep the weight balanced out in the back.

[Clyde65]

yea, I bet it will put you in gas bankruptcy if your not careful

[mannyb.]

hahahhah i know. 1 fill up would be $130 out here. im a starving student. i couldnt keep up with that. but with working full time and going to school i didnt want to have to keep stopping at the gas station 2-3 times a week

[Clyde65]

you would use the same amount of gas but $130.00 for a fill up.OMG! and I b1tch at $50.00 fill ups.

[markeb01]

When I went to an under bed tank, my truck was a daily commuter covering 400 miles a week. Having lived through the gas shortage of 70’s, I wanted the biggest tank I could fit in the space, which turned out to be 33 gallons. Now that I’m retired, it takes so long to use up the fuel I have to add STA-BIL to every tank full to keep the gas from going bad. During the winter months the tank should be kept as full as possible since it minimizes water in the gas via condensation.

http://www.driversense.com/driversense/column/524

A full load of gas in my tank weighs a little over 200 pounds. Yours can hold another 40 pounds or so. In the winter where I live the extra ballast behind the rear axle is a nice benefit for snow and ice traction. If the weight of a full tank is more than your rear springs can handle, I’d suggest using a gas dryer additive, at least occasionally.

Amazon.com: HEET 28202 Iso-HEET Premium Fuel-line...

[lakeroadster]

Gasoline weighs 6.5 lbs/gallon... 40 gallons = 260 lbs.

Nice looking truck, I would love to see those install pictures.

Question: Seems like it hangs down pretty low. You worried about that at all?

Probably wouldn't be to noticeable though with a steps bumper.

[jocko]

Nice install! Wow 40 gal! I would love to have a bigger tank - but along the lines of what Lakeroadster mentioned (and this question isn't specific to your truck) I've been looking at several of the rear tank installs that several members have done. Depending on what type of rear bumper folks install when they do these rear tank swaps (and I want to do one too), isn't there a general concern with rear-end collisions? i.e. "ka-boom"... Low hangers would of course be a concer if you got rear-ended by a wedge shaped sports car (or a large vehicle, etc) - but I'm talkin bout just getting rear-ended in general by ANYthing - seems the rear tank could be a hazard. Interested in folks' thoughts on this as this lingering thought kinda puts me on the fence about rear tanks. (granted, I'd rather have the fire in the back of my bed thna in the cab with the stock tank....)

Markeb01 - you mentioned you put a 33 gal tank in the rear? Got any pics - what was it from? I've never noticed it hangin down, so that's why I'm interested!

Thanks all for posting, this is a good thread!

[lakeroadster]

I think the best advice I have heard is to do whatever makes you feel safest.

For me personally I think having the tank in the cab is unsafe and any place other than in the closed compartment where the occupants are is better and safer.... and here is one big reason why.

The following is a post from “junkyardjohn” on the 67-72 website, post #25 on this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=117123

IN 1977 I WAS HIT BROADSIDE AT AN INTERSECTION BY A DRUNK DRIVER (I WAS DOING 55 OR 60) CAUSING ME TO ROLL END OVER END IN MY 72 3/4 TON FORD. AFTER ROLLING ABOUT 80 YARDS, I STOPPED WITH THE TRUCK UPSIDE DOWN WITH MY HEAD PINNED TO THE GROUND. IT STOPPED IN A LITTLE DEPRESSION IN THE GROUND, & EVERYTHING WAS FROZEN(IT WAS DEC. 23rd IN MICHIGAN). THE BEHIND THE SEAT TANK WAS JUST FILLED. IT SPLIT, & ALL OF THE GAS DUMPED OUT OVER ME, & ALMOST DROWED ME IN GASOLINE, AS MY HEAD WAS PINNED TO THE GROUND. I WAS PINNED IN THE WRECKAGE FOR ABOUT 20 MINUTES, I HAD PLENTY OF TIME TO PONDER THE PLACEMENT OF SUCH A FUEL TANK. THE ONLY REASON IT DIDN'T CATCH FIRE WAS MY BATTERY WAS THROWN OUT DURING ONE OF THE ROLLS. LUCKY ME-- I GOT OUT OF IT WITH A BROKEN BACK, 14 BROKEN RIBS, A BROKEN COLLAR BONE & ABOUT 300 STITCHES ON MY MELLON. SO YEAH .... IT IS KINDA A SAFETY THING.
I CONSIDER THESE TANKS A BIG BOMB BEHIND THE SEAT ALSO. THE REASON YOU DON'T HERE ABOUT ALOT OF THE PROBLEMS WITH THEM IS THAT MOST OF THE PEOPLE WHO EXPERIANCED PROBLEMS WITH THEM ARE DEAD.

JOHN

And some more data:

In 1967 the National Highway Traffic Safety Administration (NHTSA) introduced the Federal Motor Vehicle Safety Standard (FMVSS) No. 301, “Fuel System Integrity” [NHTSA Part 571.301] to reduce deaths and injuries occurring from fires. Initially the standard only applied to passenger cars, however, in 1977 light trucks were also included. GM no doubt saw thsi standard lurking on the horizon and redesigned the fuel tanks outside the passenger compartment. As far as GM's Safety vs. profit record they actually did a study on this subject in 1973:

At the heart of GM's resistance to improving the safety of its fuel systems was a cost benefit analysis done by Edward Ivey which concluded that it was not cost effective for GM to spend more than $2.20 per vehicle to prevent a fire death.

While this was certainly done in response to the side mounted tanks that were used on the "new" 1973 models, it shows that safety wasn't job one at GM, profit was.

And here is a lengthy thread from over at "The Stovebolt" that discusses "Gas Tank Safety" http://www.stovebolt.com/ubbthreads/...=628575&page=1

Happy reading!

[NCD1966]

40 gallons. I had a 1997 surburban that had a 42 gallon tank. It would cost me about 75 bucks to fill up back in 2002-03. now it would be a little over 100.

[66BowTieBoy]

Hey Mannyb,

I say fill the tank to the brim and then go see if ya can launch the front wheels.

[jocko]

THANKS Lakeroadster... That does it, I'm moving up my rear tank conversion timeline....

(I WOULD be interested in saddle tanks, but haven't seen any that hold much gas).

Thanks for that helpful reply. Bottom line makes sense - I'd rather watch a fire from inside my cab that is happening outside my cab as opposed to watching it in there with me. Fire scares the begeezers out of me.

This could be an opporunity for some intersting custom touches. Not sure if I'm up to a 57 chev-like rear light tank filler thing, but who knows. I saw a great set-up like that that someone on here (in the 67-72 section, I believe) did to their truck.

[markeb01]

Originally Posted by jocko

Markeb01 - you mentioned you put a 33 gal tank in the rear? Got any pics - what was it from? I've never noticed it hangin down, so that's why I'm interested!

I designed the tank and had it built by Rock Valley:

http://www.rockvalleyantiqueautoparts.com/catalog.htm

I just maxed out the space and set the height so it wouldn’t hang down below the fenders. Here’s a shot of when it was first installed:



It has no straps. Instead, it has very heavy end walls with side flanges built in that bolt directly to the frame rails. It’s a super clean install. It’s fully baffled and was beautifully built. The downside being, it cost over $500 ten years ago. On retirement pay I couldn’t afford it today, but I’ve certainly been happy with the investment.

It looks really big (it is) but it doesn’t really show up with the truck put together as seen below:



I originally mounted a 1967 series C10 filler neck on the driver side bed wall, under the rear fender near the top. At the time I was going to be running a hard cover on the bed, so I ran a sealed gas cap and mounted the roll over/vent valve in this location. A local muffler shop bent up a piece of exhaust tubing to connect the neck to the tank.

The setup worked perfectly - except - for one design flaw. When I designed the tank I had them fabricate an inlet elbow on top of the tank (circled in photos). The radius of the turn was too short, and unless filled at dead slow, gas would kick back, shutting off the pump nozzle. It took forever to fill 33 gallons. There was plenty of room for a longer inlet I just hadn’t considered the short radius neck a potential problem. Here are a sequence of photos showing the original fill arrangement and how it was completely hidden by the fender:











To retain the side fill arrangement, I needed to either replace the elbow on the tank with a baloney slice opening on top, or relocate the inlet to the side of the tank. Either repair would have allowed fuel to freely enter. By the time I discovered the problem the truck was my daily driver and I lived 40 miles from town, so I couldn’t afford to be without it long enough to pull the tank and have a radiator shop modify the opening. Instead I pulled the tank, filled it with water, cut a new hole and installed an aircraft gas cap directly through the floor. The tank was dried out, refilled and reinstalled in time for work on Monday.

I was really disappointed the original configuration didn’t work out, since it was very convenient to access and would have worked fine if the tank opening was modified. I’ve never seen anyone else install the filler in this location, which is a very clean solution and avoids the problems associated with a floor fill. The floor fill turned out nice, and is mounted in the left rear corner making it easier to use when the bed is loaded.