On the previous page we discussed options of factory and dealer-installed auxiliary fuel tanks. However, the aftermarket has a few options as well which we'll discuss here too, and we'll also show a few alternate installations from other truck owners.

When it comes time to installing a different fuel tank, especially if you decide to mount it in the bed of your truck, there are several things to keep in mind. First of all, you might want to check into what's legal in your area as far as fuel tanks legal for street use.

For those of you considering mounting an auxiliary tank in the bed of your truck, please remember you must be cautious when hauling cargo. In the event of a panic stop, all your bed's contents are going to shift VERY rapidly in a forward direction and could very likely puncture the tank...NOT a good thing, obviously! It's always best to add some sort of protective barrier around the tank for protection, something a bit more solid than a piece of tin. Use your imagination...maybe fabricate something from aluminum or steel diamond-plate, which is not only attractive but very sturdy.

One thing that might to come mind is installing an aftermarket fuel cell, designed for use with racing vehicles in mind. However, according to Nine Things You Should Know About Fuel Cells published on Off-RoadWeb.com:

"Currently, fuel cells are not legal for use on vehicles operated on public roads. We haven't found a fuel cell yet that has been approved for on-highway use by the Department of Transportation (D.O.T), and a fuel cell won't pass the visual inspection by a smog referee even if the factory fuel cap, filler tube, and all emission equipment are in place. What this means is that if your truck was built after 1974, you won't pass a smog inspection with a fuel cell installed. Trucks built before 1974 aren't subject to smog inspections, so you'll be safe. Any cop worth his doughnuts, however, will issue you a citation for having a fuel cell installed on your truck if he or she catches you on a public street."

Having said this, I can also say there are many people who do indeed use a fuel cell in their street-driven vehicle and have reported it's passed inspection without a hitch. However, you might want to check the local regulations to make sure.

Fig. 1  -  This owner simply removed the in-cab tank and mounted it along the front of the bed. Functional, but probably not very safe. Some sort of study barrier should be installed if the truck is to be used to haul cargo.

Fig. 2 - This '72 F-100, at first glance, appears to have been fitted with the factory auxiliary tank...

Fig. 3 - ...until you take a look in the back. You can see two tanks set up to fill from the outside.

Fig. 4 - This truck was equipped with a small fuel cell. You can bet he doesn't take many road trips in THIS truck!

When you decide you want to completely remove the in-cab fuel tank and use an auxiliary tank as your primary fuel source, you'll have to fill the existing fuel tank filler neck hole in the cab. You can either weld up the existing filler hole, or use a factory rubber plug in the hole. Pictured at right is a photo I took of a truck in a salvage yard with one of these plugs being used to fill the factory auxiliary tank hole.

The part number for a fuel tank filler plug (which the Ford catalog describes as 'Plug - Back Panel Fuel Tank Filler Pipe Opening for 67/70 F100/750) is C7TZ-8144554-A. I haven't personally tried the following sources, but have been told they might have this NOS part:

So now that you've gotten your fuel tank out of the cab, what do you do with all that extra space you now have?

Well, this first one is a shot in the dark, but if you're fortunate enough to find a factory behind-the-seat stowage compartment, it's a bolt-in. Here are a couple shots of one I found at a salvage yard. This truck I got this from was special-ordered with the in-cab tank deleted, and the 25-gallon in-frame auxiliary tank being used as the primary fuel source. The hole in the cab behind the driver's door where the in-cab tank's fuel filler neck was normally located was solid...that is, there was no hole at all:

However, since this option is one of the rarest for the '67-'72 trucks, it's highly unlikely you'll find one in a salvage yard...and if you do, be prepared to pay big bucks for it...if the seller is aware of what he has. But don't despair...if you're at all handy with tools, why not build your own? Pictured at right is an example of a setup put together in a '78 F-150 Super Cab. You could do something along these lines for your own truck. (SOURCE)