Who is going fast with the stock 3/8" fuel lines and Stage 1 pump?

I haven't seen any fuel seepage from the carb area. I'm currently running the 2 in. paper filter at the carb inlet and am waiting for the Mercury mesh filter I ordered a few days ago. I'm currently running 7 to 9 psi at idle and 8 lbs steady at cruise and no problems so far.

 

Early on I ran low 13's with my 455 '76 and had 7 lbs. at idle but only 2 going down the track with a worn out Stage 1 pump. Installed an old school Carter mechanical that held 8 lbs at idle and dropped to 6 going down the track. No change in ET/MPH. Installed a Holley Blue electric back at the trunk with regulator set at 7 and it stayed at 7 all the way down the track. Again, no change in ET/MPH. All changes were made the same day.

With a higher HP engine in the '76 I was running mid-11's with only a Comp 110 electric at the tank with stock 3/8" fuel lines. The pump is self regulated to 7 lbs. At the carb I was running about 6 down the track. Later on just to make sure I was covered for my trip to the Texas Mile I bumped the lines up to -8 everywhere and added a RobbMC 1/2" pickup in the tank. No change in 1/4 performance but there was a noticable increase in free flow (Measured by how long to pump 1 gal. of gas.) so there would be more fuel available at the carb. I did notice the pump ran quieter with less restriction at the inlet from the 1/2" pickup.

At the levels of power most of our cars are making from what I've read if you have 4 lbs at the Q-Jet inlet you are fine. In my experience with fuel delivery at WOT you either have enough or you don't. The car will let you know if it is running out of fuel. It is either going like heck or it is slowing down enough to clearly feel it, nothing subtle about it. It seems to me it would be a very, very, very fine line between slowing a car down a mph or two and just plain running out of gas. Not saying it can't happen, just that it woudl be rare. I would also think that first gear is when you will notice a drop off if you are on the edge because a car is accelerating harder in first gear(using more fuel) than it would be in third gear.

Currently my '69 GS has only a fresh Stage 1 pump and stock fuel lines and is running low 13's with a mildly modified stock appearing 400. I have as yet to measure fuel pressure but that is on the schedule. We'll see how well the pump holds up because I plan on taxing it to the tune of 11's with a much modified stock appearing 455 next year. I'll see how long the pump holds out before I may have to deem an electric booster pump necessary. With all this heat these days track time will be a long time coming so I may have to do some street testing in Mexico soon to check the pump pressure.

 

Mike, I really appreciate your experience on fuel delivery. So far, my high 12 @ 107 car is running fine with the TA Performance Stage 1 fuel pump borrowed from a friend to go along with my mods mentioned above. (still using the stock 3/8 lines). I'll post again after getting to the track but at this point I've got about 7-8 psi pressure at idle with some jitter, and a solid 7 psi at cruise. I ran it up to a little over 100 MPH on a back road yesterday and pressure dropped to about 4 psi but car was still pulling fine. That was with the ball valve on the return line almost closed down but open just enough to allow a small amount of return fuel. When the engine is shut down, the fuel pressure drops to zero very gradually.

 

By the way, if you do end up with an electric pusher pump, which one will you use? And will it also need a separate regulator or will you let the return line from the stock fuel pump continue to flow to the tank?

 

If going to hassle to put an electric pusher pump in, why not just run an electric pump only and not worry about it???

I know the slot of larger electric pumps re not very quite but some are bot too bad

 

I think adding an electric pusher would be similar in time and cost to bypassing the stock fuel pump with an electric pump only. In fact going all electric might be more as a pressure regulator might also have to be bought and plumbed in.

 

Not all electric pumps need a regulator, but all will run cooler with a bypass style installed.

 

12.7's at high 105's? All stock, no pusher pump and 71 540 4M Qjet