Fuel line size for 250

[AU Doc]

I have a ‘68 with a 250, and the pump to carb line rusted through.

I need to replace it, but I don’t know what size the line is or what size the fittings are. Are they double flared?

Any suggestions on what to use to replace it would be appreciated!

[Steeveedee]

5/16" line, iirc. The line is double-flared. The nuts are 5/16" "B-nuts".

[AU Doc]

Awesome. Thanks! Now to see if my local parts store has any line on hand. The shelves have been looking pretty thin lately.

[RustyPile]

Originally Posted by AU Doc

I have a ‘68 with a 250, and the pump to carb line rusted through.

I need to replace it, but I don’t know what size the line is or what size the fittings are. Are they double flared?

Any suggestions on what to use to replace it would be appreciated!

For future information, all tubing (we're not talking pipe here) is measured on the O.D. Most 6 cylinder I6 equipped '67 - '72 GM pickups came equipped with 5/16" fuel delivery tubing.. Your truck is over 55 years old. Anything can happen, changed, modified, and/or hacked.. Before buying up a bunch of wrong size tubing, measure what you have left. Then you'll be sure of what you have...

To answer your flare question.. Yes, fuel line is double flared.. Pre-flared brake line is a good replacement for fuel lines. They can be joined together by using a brass Flare union, and bent to shape/fit using a common "hen house" tubing bender..

[72SB]

GM used 5/16" on 6 cyl and 2 brl v8 models. 4 brl v8 got 3/8"

3/8" fuel pumps flow more gas than 5/16 ones

[AU Doc]

Originally Posted by RustyPile

For future information, all tubing (we're not talking pipe here) is measured on the O.D. Most 6 cylinder I6 equipped '67 - '72 GM pickups came equipped with 5/16" fuel delivery tubing.. Your truck is over 55 years old. Anything can happen, changed, modified, and/or hacked.. Before buying up a bunch of wrong size tubing, measure what you have left. Then you'll be sure of what you have...

To answer your flare question.. Yes, fuel line is double flared.. Pre-flared brake line is a good replacement for fuel lines. They can be joined together by using a brass Flare union, and bent to shape/fit using a common "hen house" tubing bender..

Thanks for the info, I didn't realize tubing is sized by the OD. That is good to know.

5/16" worked. I've got the new line bent up and in place. I did also learn that I need to work on my tubing bending skills

Originally Posted by 72SB

GM used 5/16" on 6 cyl and 2 brl v8 models. 4 brl v8 got 3/8"

3/8" fuel pumps flow more gas than 5/16 ones

Good to know. I think 5/16" will be more than enough for the 250 currently living in the truck

Thanks again for the info!