Fuel tank conversion

SILVERPITT

MEMBER
1985 FORD F-250
7.5L
V8
2WD
AUTOMATIC
30,000 MILES

Want to convert from a trouble-plagued dual tank system to a single rear-mounted fuel tank with a mechanical fuel pump and an inline electric fuel pump to aid in getting fuel directly to the mechanical pump and onto the holley carburetor. Want to eliminate 6 port valve switch and as many relays, switches, regulators, and as much of the wiring that I think was designed for an EFI unit. The previous owner put a fresh motor in and had so much trouble with the dual tank system system he parked it for 10 years and finally sold it to me. Everything so corroded I had to get a bucket of fuel and run a hose into carburetor just to make sure it ran. The engine has 28,000 on it with a new Holley 4180 [4160?] Sitting on top. Sounds sweet but I don't know the previous set-up. Dropped both tanks and it appears the front tank was never used. Cleaned and reinstalled rear 19 gal. Tank with elect. Pump inside. Don't need or want 2 tanks. Any help or advice on conversion would be greatly appreciated.

3 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good afternoon,

First, the pump in the tank can not be over 7 pounds of pressure. Any more than that, it will push fuel past the needle and seat in the carburetor.

What I would do is remove the pump and just use the fuel unit without a pump. Then I would run new lines to the front mechanical pump you are installing. You can put your electric pump on the fuel feed line to the pump but it must be at the low level of the tank. If you put it too high, it will not draw the fuel from the tank and will pump air.

As far as the switching valve and the lines, you can just remove them along with the other tank and keep them aside.

Roy