Moved to the "Hudson" forum category

I would think that the fuel line should be 5/16" tubing and the brake lines are 3/16" tubing.

The early (pre Step-down) brake lines are 1/4" and I'd assume that the fuel lines are 5/16ths (they are on all I've seen), however, I use 1/4" between the pump and carb(ie) for a couple of reasons: The smaller line reduces the "heat soak" effect in the engine bay by reducing the surface area; the smaller diameter increases the flow rate/velocity through the line, thus reducing the amount of time it spends in that segment (also cutting heat-soak time) and......that engine can't burn fuel fast enough to make a 5/16 line necessary. I have changed the engine bay lines in our '47 212, '54 202 and "Twin-H" Hornet to 1/4" without any issues with fuel starvation. Going racing? It might not be for you, but for a stock car in ordinary driving, it has proven to be effective.
Frank

Exactly what I needed to know. Now I can use up my old stock of tubing,
You know what they say" I line is a terrible thing to Waste"

groan

Don't take my word for it. Others may have differing opinions but it has worked fine for me, although I must admit to being in a much cooler climate so the ol' vapor lock issue isn't as much of a concern.
F

On the 37 Terraplane we restored I found an original copper line with fittings that I polished up and installed. That line was 5/16.

On the 37 Terraplane we restored I found an original copper line with fittings from old parts car that I polished up and installed. That line was 5/16.

I wouldn't use copper for a fuel line. To much chance it will break. I think steel fuel line tubing is available in 5/16". Definitely copper is a no no for brake lines.

Hudsonly,
Alex B

The copper fuel line I used was 79 years old and off another 37 Hudson chassis I had. The goal was to make this car has correct has possible. I am glad I found an original copper fuel line. It looked good polished up.