The Stovebolt Site Forums The Shop Area General Truck Talk Fuel tank/line question (51 half-ton)

The fuel line comes out of the bottom of the tank on mine. My new sending unit has a fitting for the fuel line which would put the fuel line at the top of the tank.

The Factory Assembly Manual shows the fuel line coming from the sending unit at the top. Sine the person who did all of the work on the truck until now half-[censored]ed everything else I'm wondering which is correct... top or bottom?

Top, from the bottom It'll suck up any debris that could be in the tank.I've seen people do that before, drives me nut's, they are to lazy to drop the tank and fix correctly,when in all reality it's just as much work to cobble it from the bottom.

That's correct for your year truck Woody, it gravity feed to the fuel pump from 1947-53. After that the later ones sucked it out of the top through a tube with a screen on it.
Also be aware that the Assembly manual illustrations are for 1953 & 1954 models so they don't always apply to the earlier AD's. Ya can’t blame everything on the PO, the GM engineers deserve some credit also.
Denny Graham
Sandwich, IL

Okay, what about a later engine? I'm about to swap out the 216 for a 235.

And if I should change to the top line, where can I get that metal line? I don't see it in any vendor catalog.

The sending unit you have is for a later truck and you could just put a plug over the fuel line. As long as you have a filter between the tank and pump the bottom fitting is original for your truck and should not give problems except for maybe some crud sticking in the valve. The valve at the bottom allows you to shut off the fuel and this will be lost with a modification to the top.

Curt B.

Thanks for the responses so far but the question remains, is the fuel pump on the 235 such that the fuel line can be run from the sending unit or should I just leave it at the bottom?

The fuel pump doesn't care where it's pumping from. All it knows is suck and squirt.

Gee Cletis, you have such a way with words.

Now, if one were to pressurize the fuel resevoir with the ehaust from the engine,,,, using a baffle in the exhaust for a spark arrestor, one could have a turbocharged fuel delivery system foregoing a need for that old mechanical fuelpump...

Oh yeah, that would work real nice,,you'd also get all the moisture from the exhaust in the tank too.
.......Where do they come up with these ideas?

I cannot believe someone took me seriously

Nuance is sometimes difficult to communicate in written language. That's where the gramlens come in handy.

When I said that it gravity feed to the fuel pulp I didn't mean the that was nessasary for the fuel pump to suuuuck the fuel up. It just so happens to be a factor with the bottom feeder. All the diaphram pumps have about the same pull and create about the same output pressure.
Denny Graham
Sandwich, IL

Thank you Denny, that answers my question.

It's safe to assume that if the fuel pump is below the level of fuel in the tank the fuel will naturally syphon to the pump anyway, so there is positive pressure at the pump regardless if the pipe that comes out of the tank goes through the top or bottom.