My car still has the stock fuel lines and a holley red fuel pump with a trunk mounted cell. I was wondering at what point do they become a restriction. thanks
Not to be a smart alec.. but basically when you can't keep your carb full and your fuel pressure falls during a run. Holly has some good info about general fuel delivery: http://www.holley.com/data/TechService/Technical/Fuel%20Pump%20Tech%20Info.pdf
I sort of agree, put a fuel psi gauge on it and see what you have going thru the traps. barry grant use to have a add in national dragster about the filling a one gallon fuel can, I think you need to fill the can in 25 seconds for an 11 second car, and 20 seconds for a 10 second car. but I know cars that go faster than they should with small fuel systems. how fast is your car?
Back when I had my old 70 Maverick, I had a decent 351W/C4 combo in it that ran mid to high 12's...... That was with a stock tank/line and a cheapo replacement mechanical fuel pump..... I thought that was hurting it in the 1/4, so I put a sump in the tank, ran -8 fuel line all the way up front and ran a Holley blue pump with regulator..... To my surprise the car ran exactly the same.....
I'd say the stock lines are fine, it really depends on how many filters you have before the pump and after the pump..............and how much restriction you have at the carb. On my race car I use 8 fuel line all the way to the carb, but I have a 100 micron filter before the fuel pump, and a 40 micron before the carb.........I also have a fuel cell in the trunk. My Mallory 250 (which was just refurbished by Mallory (Prestolite) was in the car because the guy before me ran Alcohol..............but it does have feedback for over pressure to the tank.
My 69.5 has 3/8" stock. That's plenty for any street engine and most mild drag motors. Watch the square corners at fittings and lots of bends, that hurts as much as diameter. SPark
