Fuel line size

[usraptr]

I want to replace my fuel lines when I begin reassembly.  I've noticed that most manufactures, Flea bay, etc offer both a 3/8" and a 5/16" fuel lines for a '70 'Cuda.  My car is a 440 U code, 4 speed with 4.10 dana rear.  Which size fuel line should I be running?   Did a search and couldn't find any info on this.  Also, I purchased a new fuel tank and need a new sending unit.  Once again I see fuel sending units with 3/8" line and 1/2" lines.  Which is correct for my engine/year combo?
Thanks in advance.

Brad

[Matt70]

I'm pretty sure 3/8 lines were for 440 6 packs and hemi cars. Though some folks have cars with the 5/16 lines and upgraded to big block high horse power engines with no adverse affects.  Matt

[dodj]

The factory supplied 3/8" fuel lines for BB.

I'm pretty sure 3/8 lines were for 440 6 packs and hemi cars. Though some folks have cars with the 5/16 lines and upgraded to big block high horse power engines with no adverse affects.  Matt

My car was originally a 318 with 5/16" fuel lines. Changed to a 440 and ran with the 5/16" for 10 years with no adverse affects (that I could tell). But my 440 is pretty much a stock engine.

[73Chally]

You should be fine with the 5/16", but if you're putting in a new line anyways, I would go with the 3/8".  With that said, I went from a 340 to a 440 6 pack with the original 5/16 line for a couple years with no noticeable ill effect, although I did upgrade to a 3/8 a couple years ago.

If the question is, do I need the 3/8 line, I would say the answer is no, but, what are your future plans for the engine?

[ksierens]

My 70 U code Challenger came with 3/8" fuel line and a 1/4" return line from the vapor seperator by the fuel pump.  With out it, you can vapor lock on hot days.

[usraptr]

Thanks everybody,  I'll go with the 3/8" lines.  I assume that means that I want the fuel tank sending unit with the 1/2" lines?

Brad

[73Chally]

3/8 inch sending unit.

[usraptr]

Duh, that makes sense.      Thanks