I was wondering how much power you can get when your using a 5/16 fuel line?

 

There's too many variables to be accurate. A guess would be 300 to 350 hp depending on carb. size and rpm. I know when I put the 383 in my 84 I had to completely redo the fuel system as I was sucking the bowls dry half way through 3rd.

 

Using a small electic booster pump back by the tank (Holley Red) along with a good mechanical pump up on the engine (Carter 6PSI street pump) has gotten me WAY past 500HP on 3/8" fuel lines.

On a smaller 5/16" line I have limited experience, but when I put this system on a friend's 72 Chevelle with a warmed-over 383, reusing his stock pea-shooter 5/16" line, it's been working just fine to go 12.2 @ 113 with no drop in fuel pressure anywhere during the run.

 

It will be feeding A Built 468. It has a edelbrock machanical pump It's going to spin about 6500 rpm with a 850 carb.

 

Minimum 3/8" line (-6 or #6). If you can run 1/2" (-8 or #8), then do it.

I have a fuel cell mounted in the front. I run 5/8" line from the tank to the pump to the regulator then 1/2" lines from the regulator to the 4 float bowls (tunnel ram with two 850's running on alcohol)

Personally I don't think you need to go bigger than 3/8" but 5/16" will be too small.

 

If that engine will make close to 600 horses, you'll have to go to 1/2 inch fuel line. If only 500 or so, a 3/8 should do it.