Bigger Gas Tank...

[DuceAnAHalf]

Now that someone mentioned an after market tank I am considering two smaller ones that will fit on each hump in the trunk. An extra 10-15 gallons would be great actually. I would defiantly have to get new springs if I were to do this upgrade.

DO you mean on the humps or between the humps and the body?

[saiyaneye]

The humps, not the crease in between them and the side of the car. What is the max measurement of a "cube" that can fit on that hump?

[Tiggie]

Did the 79's use a 20 gallon tank or am I just imagining?

Yes, so did 1980-1982 Sedans at least. I've got a 20 gallon.

[gadget73]

Sorry man, but I didn't understand a word - how does shortening the filler neck increase the tank's capacity? Also what is that bag with hose and clamps, and how do you use it?

If the fill neck extends down into the tank more, it will cause fuel to back up into the neck once it hits the bottom of the filler neck because at that point air can't escape from the tank. The bag with the hose is just a different length rubber piece that goes onto the end of the steel filler neck so it extends different amounts into the tank. If you got a truck with the larger capacity fuel tank, all they'd do is pull the fill neck, remove whatever length piece was on there, and install the new, shorter hose on the end of the filler neck.

[Nathan in MI]

Yes, so did 1980-1982 Sedans at least. I've got a 20 gallon.

Police cars also got 20 gallon tanks.

[saiyaneye]

I have 18 gallon in my '81 Tiggie

[Tiggie]

I have 18 gallon in my '81 Tiggie

Well I can say that all '82's sedans got a 20 gallon tank. That's what my owners manual says, my service manual, my specifications book, my dealership brochure and every peice of factory literature I have. But that is only for '82's. I would have thought the earlier ones had the bigger one too, but I guess not. Interesting.

[Archangel]

If the fill neck extends down into the tank more, it will cause fuel to back up into the neck once it hits the bottom of the filler neck because at that point air can't escape from the tank. The bag with the hose is just a different length rubber piece that goes onto the end of the steel filler neck so it extends different amounts into the tank. If you got a truck with the larger capacity fuel tank, all they'd do is pull the fill neck, remove whatever length piece was on there, and install the new, shorter hose on the end of the filler neck.

Ah, okay then. So if I just shorten my filler neck the tank will hold 20 gallons?

[gadget73]

Should, yes. Not really sure if its worth the effort but thats a different argument.