Need help on fuel tank to fuel pump hard line size for big block

[1963c-10]

Normally I'm in the 60-66 section, but need some input from the guys with factory big blocks in the 67-72 trucks.

Was the factory big block truck hard line from the tank to the fuel pumps 5/16" or 3/8"?
In the 1st gen c-10s it seems the 6cyl/and sb motors were 5/16". But chevy has a listing for a 3/8" line also.

I'm just wondering what line the big blocks had so I can get a 3/8" hard line if needed.

Just done with a big block conversion in my 63 and I want to make sure the fuel delivery is adequate to the fuel pump.

Thanks for any help in advance.

[In The Ten Ring]

I don't know, but I'll bet it is 3/8 inch. No, I am sure it is. I asked on here many times about that and 3/8 was suggested for the bigger engines.

Will you bend your own tubing?

I am about to finish that task, I used a Rigid tube cutter, Harbor Fake Tools bender, Craftsman flaring kit, and Poly Armor tubing. It was a very annoying job as I don't have a lift and I am working alone.

I would suggest one of those Eastwood tube straighteners and a better bender than what I had.

[1963c-10]

Thanks for the reply. I've had inline tubes do all my brake lines so far and I'll probably just have them bend one for me out of stainless steel.

Thanks for the help.

I also work alone, but my projects getting closer to completion. Then the 63 short fleet will begin. Have a 348 big block to install in that one.

And a couple pics of the current project.

[In The Ten Ring]

OMGosh! She's gorgeous!

I bought the line from fuel pump to carb from In Line Tube since I knew my bender couldn't handle such tight bends. It's stainless steel.

You have tow hooks on a 2-wheel drive?

[1963c-10]

Thanks for the compliments. Still a work in progress, but shes getting there. I do all my own work, paint, electric, etc.....everything but the short block. I have a great local machinist for that.

Yeah, the tow hooks was an option for our trucks also. Same from 60-68 I believe.
I mill a lot of wood here and still use my trucks so the hooks come in handy moving logs around on the property.

[oldertruckfan]

my factory 71 big block was a 3/8 fuel line. I remember that because I had to swap out the sending unit

[1963c-10]

Originally Posted by oldertruckfan

my factory 71 big block was a 3/8 fuel line. I remember that because I had to swap out the sending unit

Thanks for the input. Got one enroute from Inline Tubes in stainless steel.