Oversize front tank?

Does anyone know of a source for a larger front tank for a short wheelbase truck? I need to get back on my F100 project. I hate the fact that it has only a 16 gallon tank. I want either a larger front tank, or I'll convert to a Bronco rear tank if necessary. It's an '81 stepside, so my preference is to stay with only a front tank.

There is no room on a Flare Side to install a larger tank unless it is a custom one.
I tried to install a 19 gallon tank and no way it would fit.

So you have 2 options at this point, well 3 if you look at custom front tank.
You can install a factory 19 gallon rear tank or the Bronco tank as you said.

I believe to install either rear tank (you will have to for the factory tank) you will need to change out the cross member just in front of where the rear tanks fits as the Flare Side one is not made for the straps to hold a rear tank.

You should be able to use any 80 to mid 90's rear tank just note the 87> have a different filler neck & vent you would need to deal with but it is the better of the vent systems and you would already have the tank end taken care of so it would be just the filler end.

You then have how to switch between the 2 tanks?
I can tell you the wiring harnesses for single & dual tanks are different.
You did not say what motor / fuel system you have as that can add a wrench to this.
I have a 300 six and the easiest dual tank system there is.
I used the full wiring harness from a parts truck, also a 300 six truck, that had dual tanks. That is what everything came from for my truck.
Again not knowing the motor / fuel system I cant really get into how you should go but like me it might be best to find a parts truck of the same motor / fuel system to get the parts from?

Now how to fill this rear tank?
You looking to make it look factory or hide it and just so you can get gas in it?
Me I wanted it to look factory and my brother sent me a Flare Side door and part of the fender.
I then fiber glassed it to the Flare Side fender to make it look factory.



A style side door and "bucket" behind the body is different and cant or I did not want to use it.
The rubber hose and vents from a style side and Flare Side can be used to make it all work.
I dont remember just what all I used as the factory Flare side was messed with before I got my truck.
But between that mess, the 2 from the parts truck style side and what my brother gave me I was able to make it all work and look factory.





What it looks like all done

Oh also the above is also based on skill level, tools and the place to do the work.
I did all the work myself no farming it out and why I know how it was done and the pictures to prove it.
Any questions ask
Dave ----

Oh I forgot the other option on the fuel door if only running a rear tank is to move it from the front to the rear.
If done right both parts you cut out can be swapped and glassed back in to fill the holes.

Or you can just see about having the filler neck hang out in the wheel well area like you see on some flat bed trucks.

Maybe have it come thru the floor?
I use my truck so that was not an option and to drop the tail gate for gas is a PITA

You did not say if you will be running a spare under the rear tank but if so I dont know if you can with the Bronco one? The factory 19 gallon I do run the factory spare under the tank.

I dont have a picture of it but the tank switch is factory to the right of the HVAC control and works the gauge like the factory did.
Dave ----

If I go with the Bronco tank, the plan was a 38 gallon rear and delete the front tank completely. Engine is a carbureted 302, so I'd just need to extend the fuel feed line and sender harness.
On one hand, I hate to lose the under bed spare, but they're such a pain to remove when needed that I really don't think I'll miss it.

Thanks for the advice on the filler door and hose. I was hoping it would be as easy as just moving the door to the back of the fender.

That is am impressive write up! beautiful work. In looking at it it looks like the fenders are quite similar to dually fenders.

I agree!  Well done, Dave!  Both for the work as well as the writeup.  

Thanks guys

As fore the fenders being the same well yes and no.
They are both fiberglass but you can not use either one on the other truck.
The flare side bed side is flat so the bolt side of the fender is flat.

The dually bolts to a style side bed, they cut the wheel opening bigger to clear the wheels.
The style side bed side has body lines the fender follows.

I dont remember now if the fuel doors of the dually are the same as the flare side or the style side?
I want to say style side as I think the fenders are shaped like the style side. they have a curve to them.
And yes the doors and the "buckets" behind are different between them. I do have pictures of then too.
Dave ----

Dave, the doors on the dually are flat and the buckets behind them look the same as your picture.

They do look the same till they get put next to each other
Brown is the flare side / silver style side.
You can see the door blot spacing is different and so is the bucket.

Size difference of doors

The curve to follow body shapes

I just dont remember if the 2 that fit fenders or the same or not?
I think Gary looked it up once I just forgot what they all fit.

BTW here is a style side bucket with door (silver) other wise they all look the same.

Dave ----

The doors on the dually are flat, so they may be the same as the Flareside. I do know that filling Darth's tanks with the original vent setup was a nightmare. The vent tube would get gas running over the end and would "burp" a slug of gas back up it.

I changed Darth's to the later style where the functions are reversed, gas runs down the inside tube and the outside is the vent.

If it is flat then they must be the same I just could not remember when we looked it up back when.

As for the filler vent when I put mine back together I made sure the vent was long enough to stay put at both ends where they should fit into holders. I can fill both tanks as fast as the pump will pump.

Only 1 time did I have a issue with the rear tank filling, only took line 2 gallons?
I gave up and when I got in and flipped the switch the tank was full
Other wise it only hurts when I fill because of what it takes to fill both tanks $$$
Dave ----

Tell me about the cost, 38 gals at 10 mpg.