Converting from dual saddle tanks to a single fuel tank

[Bennyt]

$$$$ though. Those are more the high $ hot rod build category.

They start as low as $400 online for a bolt in tank needing no real mods.

OP is also posting about buying Dakota dash, disc conversions, etc so I think an extra $100-200 for an easy solution isn't crazy.

 

[Grit dog]

They start as low as $400 online for a bolt in tank needing no real mods.

OP is also posting about buying Dakota dash, disc conversions, etc so I think an extra $100-200 for an easy solution isn't crazy.

Good point. I lost track, confused OP with the discussion in this thread about scavenging parts and odd old tank setups.
Regardless, there is every OE option for these trucks readily available and reasonably priced, which seems pretty easy to me if you can just put it where GM did. Especially if you’re not trying to recreate non factory fuel filler options/locations.

 

[WhiteR30]

curious to know the reason for terminating the saddle tanks.

Also, will this addition affect your spare tire location?

 

[Mike_82_Shortbox]

I'm curious to hear from those who have done this

Don't. Those saddle tanks are up out of the way, they're protected, and they hold 32 gallons of fuel. There's no we can get that in a single fuel-cell sitting between the frame rails. Not to mention the fact that there's no place to put a 32 gallon fuel tank between the frame rails and keep it up off the ground, even in your truck. Now what about a filler neck? You have to keep the filler pipe either behind the wheel tubs, or ahead of them, because you can't go over them. Or through them. For the stock filler locations, there's no way to get rid of the side tanks and put in a single central tank, because the transmission and driveline is in the way. So you're stuck with the rear, and that means you have to go just behind the differential and ahead of the bumper, and stay between the frame rails. That's not 32 gallons. If the stock dual-tank fuel system in your truck is working, there's no practical reason to get rid of it and change it to something that's less convenient, has less capacity, and is more prone to sustaining damage. If the stock system doesn't work, it's still cheaper and easier to just fix it, and the benefit is greater.

Good luck!

 

[75gmck25]

Unless you just like a challenge, or this is part of a bigger EFI conversion project, using the original dual saddle tanks, with a mechanical pump, and bringing them back to life is the simplest and cheapest way to go. Nearly all the parts are available from either junkyard or as new parts, and they are relatively inexpensive (compared to new electric fuel pumps, etc.). The wiring diagrams and fuel line routing are simple if you are willing to read the repair manual.

The only required part that is no longer available is the 6 port Pollack valve with a single electrical terminal (used on the older trucks), which means you may need to upgrade to the newer Pollack valve with multiple electrical terminals, and the matching dash switch.

 

[Ricko1966]

curious to know the reason for terminating the saddle tanks.

Also, will this addition affect your spare tire location?

You will lose your spare tire location and will have to carry your spare elsewhere. I dont understand the appeal of a rear tank myself but to each each their own.

 

[Grit dog]

Don't. Those saddle tanks are up out of the way, they're protected, and they hold 32 gallons of fuel. There's no we can get that in a single fuel-cell sitting between the frame rails. Not to mention the fact that there's no place to put a 32 gallon fuel tank between the frame rails and keep it up off the ground, even in your truck. Now what about a filler neck? You have to keep the filler pipe either behind the wheel tubs, or ahead of them, because you can't go over them. Or through them. For the stock filler locations, there's no way to get rid of the side tanks and put in a single central tank, because the transmission and driveline is in the way. So you're stuck with the rear, and that means you have to go just behind the differential and ahead of the bumper, and stay between the frame rails. That's not 32 gallons. If the stock dual-tank fuel system in your truck is working, there's no practical reason to get rid of it and change it to something that's less convenient, has less capacity, and is more prone to sustaining damage. If the stock system doesn't work, it's still cheaper and easier to just fix it, and the benefit is greater.

Good luck!

The OP is now keeping dual tanks but even a shortbed will hold an oe style 31 gal tank in back and not hang down.
In fact the only tanks on these trucks that are even remotely visible are the early aftermarket tanks. Got one on my oe single tank 77 and it’s a couple inches deeper than oe.

 

[WhiteR30]

You will lose your spare tire location and will have to carry your spare elsewhere. I dont understand the appeal of a rear tank myself but to each each their own.

I do not understand the appeal as well. You are not gaining any capacity removing ( 2 ) X 16 gallon saddle tanks on short beds or ( 2 ) X 20 gallon tanks on long beds. I would rather keep the spare out of the bed, it allows more room for camping gear, hunting gear, or gear for race car . I think a lot of the issue to the saddle tank removal goes back to the Dateline episode which demonized the saddle tanks, in which the episode was debunked after the airing....

 

[Grit dog]

^On the contrary, I’d say very few square owners see it as a safety issue. Predominately I think many are trying to simplify and old/wore out/backed up dual tank system and view a single tank as easier or more reliable.
Being old enough that I was around/driving/working on these when they were just normal newer trucks, my opinion is it’s a pretty reliable and simple setup. Biggest issue being difficulty in finding one particular type of selector valve and the workaround for that and having to do 2 of everything if overhauling the fuel system.
I think it’s cool/vintage…whatever.
And until recently the OEMs have not ever had as much fuel capacity as the ole dual tank trucks. Even now, I think it’s only Frod and Ram that offer 50 gal tanks and only on HD Longbeds I believe.

 

[bucket]

The appeal is the simplicity of a single tank and only having one fill point as well.

I never found the fill points on both sides to be annoying back when little old gas stations were still common. It was pretty easy just to pull up between two pumps and have the hoses reach each side. But now the majority of gas stations all seem to be renovated and everything is more spread out. Although I have come across a number of travel stops (maybe all Pilot and Flying J) the last couple years that have satellite gas pumps for rv's. Those are very handy for our old dual tank trucks.

 

[WhiteR30]

One thing you never hear is, the conversation of equalizing the dual tanks, which would work better on carbureted trucks. I would not be that hard to have a radiator shop weld connections on the front or read toward the bottom, connect the two, add a tee, go to pump on block.
I would rather have dual working tanks.....

 

[Ricko1966]

One thing you never hear is, the conversation of equalizing the dual tanks, which would work better on carbureted trucks. I would not be that hard to have a radiator shop weld connections on the front or read toward the bottom, connect the two, add a tee, go to pump on block.
I would rather have dual working tanks.....

Lots of people have talked about it. Nobody runs siphon feed anymore.