Can’t decide on single or dual tanks

[boltbrain]

One of my dual tanks in my 79 K20 developed a rust leak while I had it out cleaning it up, replacing the sender. So I thought this would be a good time to swap both tanks for a single and I got a 31 gallon tank from a 75 Suburban. Both type senders should work with the gauge as both are 95 ohms max. I made mounts, just by bolting 3 pieces of 3/16 plate steel to the underside of the crossmembers, one of which is under the rear of the cab. The tank will fit in ok. I haven’t driven this much since I got it and am just curious if there’s some reason I’m not aware of to stick with duals. One issue I have with duals is that to fill both up you have to hang up the spout and move the truck. The other issue is safety, having the tanks outside the frame. This is a flatbed so there isn’t even any body metal for protection. I have read however, there have been few fatalities over the years from this. On the other hand, the roads here can get icy. I would much appreciate any opinion on your preferred tank setup as I am “ six of one half dozen of the other”.

 

[WFO]

NBC Admits It Rigged Crash, Settles GM Suit​

NBC Admits It Rigged Crash, Settles GM Suit

In an extraordinary public apology, NBC said Tuesday night that it erred in staging a fiery test crash of a General Motors pickup truck for its "Dateline NBC" news program and agreed to settle a defamation suit filed by the auto maker.

www.latimes.com

 

[TotalyHucked]

The crash/safety hazard is really a null and void argument. I'd go with the single rear tank just for simplicity sake. Less hassle to fill, don't have to deal with failed switcher valves/etc.

 

[Bextreme04]

I went from dual 20 gal to a single 31 gallon suburban tank in my 1980 K25 just for simplicity in the EFI conversion. I'm using a 90's tank with the baffle inside and an EFI blazer sending unit. I put a straight pipe in it with a sock for now so that the mechanical pump isn'e trying to suck through the electric pump. When I put the new EFI 454 in, I'll just swap the straight pipe and sock for the EP381 pump I have for it.

 

[boltbrain]

The crash/safety hazard is really a null and void argument. I'd go with the single rear tank just for simplicity sake. Less hassle to fill, don't have to deal with failed switcher valves/etc.

I saw somewhere the rear center recommended but I hung my spare tire there with the little winch, so put it between the two crossmembers behind the cab. I’ll put up pictures in a few weeks. It’s kind of close but I glued some plastic and rubber here and there, ran the straps over the top instead of underneath, and made strap type shackles instead of 1/2 bolts holding the 4x4 wood frame bed down in order to give me 1/2” more space. Also since the bottoms of the crossmembers are off level by 1 1/4” I put a spacer of aluminum bar on top of the rear mount ( plate) to drop it 1/2”.
Just in case anybody is interested.

 

[boltbrain]

I went from dual 20 gal to a single 31 gallon suburban tank in my 1980 K25 just for simplicity in the EFI conversion. I'm using a 90's tank with the baffle inside and an EFI blazer sending unit. I put a straight pipe in it with a sock for now so that the mechanical pump isn'e trying to suck through the electric pump. When I put the new EFI 454 in, I'll just swap the straight pipe and sock for the EP381 pump I have for it.

The EP381 is an in-tank pump? For the 90s Suburban?

 

[SquareRoot]

One issue I have with duals is that to fill both up you have to hang up the spout and move the truck. The other issue is safety, having the tanks outside the frame.

So don't run both tanks to empty at the same time.
I thought the burb tank went between the rails behind the axle. How are you fitting it behind the cab without interfering with the driveshaft? We're going to need pics of this contraption.

 

[boltbrain]

Ill see if I can get pictures posted from this phone but may need to wait until I get to my computer in town. Look at your cross members, I bolted 3/16 plate to the bottom of the hat, so to speak. The crossmembers are made of hat channel. My three plates each bolt to both sides ( both brims) on the crossmembers, for strength. They extend 3” to give the bottom two edges of the tank that are parallel to the inlet pipe, a place to sit. I used liquid nails to glue topper weatherproof rubber into those plates where the tank sits. To keep the tank from sliding forward I glued two layers of conveyer belt rubber to the side of the front member that the side if the tank would otherwise touch. I did not grind or modify the tank in any way. The spout goes to the right side like in the Suburban. The straps keep it from moving side to side. Last thing is to fill the 1/2” space left between the rearward crossmember and tank. After snugging the tank forward to the two rubber stoppers of conveyer belt I glued another piece of rubber belt to a piece if angle and put the two between tank and side if member, and drilled holes throo the other, horizontal, side of the angle now resting in top of Xmember, throo Xmember, bolted throo both with 5/16 bolt. It’s easy to access that rear angle/ rubber stopper cuz it’s wide open from the rear.
Driveshaft and both mufflers are about 5” below the tank, just guessing.
Both crossmembers have gussets from the channel rails riveted to them. I just put my 3/16 plates where the gussets were not. So the plates support the front and rear of the bottom of the tank.
The thing I didn’t like about it is the inlet tube will cut into the bed about a foot from the outer edge. But this is a flatbed, and I’ll have it in a toolbox. Open the toolbox to fill it up. With a sideways facing door that drops down. I don’t want the bed higher. the tube AT THE TANK is just below the bed boards, levelI’m going back to the wrecker’s to get the Suburban spout off the body. The outer 8” curves up

So don't run both tanks to empty at the same time.
I thought the burb tank went between the rails behind the axle. How are you fitting it behind the cab without interfering with the driveshaft? We're going to need pics of this contraption.

 

[boltbrain]

Here’s some pictures, hope they go ok never tried it before

 

[boltbrain]

Didn’t give it enough time to load here’s two

 

[boltbrain]

Two more

 

[GTX63]

My first truck, many years ago, was a 79 K10. It had dual tanks, which I thought was a cool feature at the time.
This was before pay at the pump and debit cards, so filling both tanks meant the clerk was inside, phone in hand, ready to call 911 every time I left the pump to fill the other side. Or I had to go in, guess the amount and pay cash up front.
Anyway, it was a Christmas eve and I was driving my wife 300 miles to see her parents. No issues on the way up. Coming back the next evening, in a blizzard, I went to switch tanks. Uh oh, the switchie no workie. The switching valve, whether frozen or junk, had failed. 16 gallons of fuel @ 10mpg= less than 300 miles. Back then, on Christmas Day night, most gas stations were closed.
Me, not being as dumb as I look, had two 5 gallon jugs of fuel in the bed for just such an event.
I currently have an 80 K15 with dual tanks under restoration now. My druthers are to keep and run on one tank until I figure out a larger one tank solution.

 

[TotalyHucked]

My first truck, many years ago, was a 79 K10. It had dual tanks, which I thought was a cool feature at the time.
This was before pay at the pump and debit cards, so filling both tanks meant the clerk was inside, phone in hand, ready to call 911 every time I left the pump to fill the other side. Or I had to go in, guess the amount and pay cash up front.
Anyway, it was a Christmas eve and I was driving my wife 300 miles to see her parents. No issues on the way up. Coming back the next evening, in a blizzard, I went to switch tanks. Uh oh, the switchie no workie. The switching valve, whether frozen or junk, had failed. 16 gallons of fuel @ 10mpg= less than 300 miles. Back then, on Christmas Day night, most gas stations were closed.
Me, not being as dumb as I look, had two 5 gallon jugs of fuel in the bed for just such an event.
I currently have an 80 K15 with dual tanks under restoration now. My druthers are to keep and run on one tank until I figure out a larger one tank solution.

My buddy's '86 is a dual tank truck. The driver's tank feeds the engine, the pass just has an in tank pump run over to the driver's tank, so he can fill it going down the road. Anytime we stop for fuel, he just tops off the pass tank. That could be an option for ya

 

[Grit dog]

One of my dual tanks in my 79 K20 developed a rust leak while I had it out cleaning it up, replacing the sender. So I thought this would be a good time to swap both tanks for a single and I got a 31 gallon tank from a 75 Suburban. Both type senders should work with the gauge as both are 95 ohms max. I made mounts, just by bolting 3 pieces of 3/16 plate steel to the underside of the crossmembers, one of which is under the rear of the cab. The tank will fit in ok. I haven’t driven this much since I got it and am just curious if there’s some reason I’m not aware of to stick with duals. One issue I have with duals is that to fill both up you have to hang up the spout and move the truck. The other issue is safety, having the tanks outside the frame. This is a flatbed so there isn’t even any body metal for protection. I have read however, there have been few fatalities over the years from this. On the other hand, the roads here can get icy. I would much appreciate any opinion on your preferred tank setup as I am “ six of one half dozen of the other”.

Well, Montana is a big state. Especially if you're driving a gas sucking 40 year old truck around. Take a half tank just to get to the grocery store in most places!
The move the truck to fill the other tank argument is almost a moot point, considering many gas stations are set up to fill either side, long enough hose and no issue with dragging the hose across with a flatbed.
The safety issue is moot as well, IMO.
That said, the Blazer tank is a simple troublefree solution and there's no hidden reasons to keep the dual tanks in the OE location.
31 gal vs 40. But 71 gal sounds really cool! (If you are actually piling on the miles and long drives)
Or if you have one good saddle tank, and you already have the rear tank, a dual tank setup for 51 gal is an option as well.

 

[Bextreme04]

The EP381 is an in-tank pump? For the 90s Suburban?

EP381 is the high pressure in-tank pump from a 96-2000 truck with Vortec motors. This one was in my donor 97 K2500 Suburban that I pulled the 454/4L80e out of