Gas tank sending unit & 3/8 fuel line

[SideStepper]

On my 55 2nd series truck I dropped in a 402 big block engine. I would like to keep my stock gas tank & run 3/8" fuel lines using a electric fuel pump. The problem is finding a sending unit designed with a 3/8" diameter tube & fitting, which is configure to fit the GM factory style gas tank (the replacement stock sending units use 5/16" lines).

Does anyone have a source for a gas tank sending unit or any suggestions on how to work around this problem?

[1project2many]

It's a simple job to remove the 5/16" line and braze in 3/8" in it's place. A radiator repair shop is just one place that could do this. I actually built a complete sender using parts of the stock unit so I could install an electric pump in tank during my EFI conversion. 3/8" supply line and 5/16" return.

It's also a good idea to add baffles in the tank to prevent fuel from sloshing to the side during cornering. On the stock, low power engine a little fuel starvation wouldn't hurt but that 402 might not like running lean.

[Stepside Jim]

SideStepper, I had the same issue/concerns as I too am putting a 396/402 in my 57.

Yes, I noticed the line is 5/16", but when it makes tha couple sharp bends and where the threaded end is on the line I figure we're down to about 1/4".

I may have taken the difficult road, but my solution was to start all over.

I did get a 30 ohm universal sender from Classic parts, then fabricated from there.

Good luck, Jim

[SideStepper]

Well if you want something done right..........you have to do it yourself.
You guys have brought up some good points on adding baffles & the modifcation of the available sending units to the larger size 3/8" pickup tube. Also, I didn't even think about the tight bend radius on the existing senders restricting the fuel flow even more. With most of our trucks running either small & big block performance engines, I find it hard to believe, that not one aftermarket parts company out there, isn't making money on this problem.
While on the subject, what electric fuel pump are you using? How many GPM does a Big Block with a Q-Jet carb require?

[Stepside Jim]

I agree, I searched far and wide for an aftermarket with larger tubing.

I suppose many will say that the market would be small due to the amount of people who move the tanks to the back of the truck.

I am going to use a Holley mechanical pump, yet in the past I have used a Holley street performance electric pump with a preset pressure around 6 to 7 pounds. I used it with a 396 and Q-jet, no problems.

I got away from the electric pump only because I didn't want to hear it running all the time. I did use a hidden switch for the pump which paid off when I had a neighbor, joking around, wanted to move my car. He got about 50 feet and it died, I don't have that option with the mechanical pump.

Jim

[_Ogre]

nice fix stepside.
you may have the solution to my fuel gauge problem in my custom aluminum rear tank as well. the universal gauge they sent with the tank mounts on top and swings into a baffle in the tank, no matter how i bend the rod. mounting it mid tank with that short rod may be my solution. very nice work.

[Stepside Jim]

Thanks _Ogre, I appreciate the compliment.