I have a 477 tall block with no fuel boss some I'm running an electric Holley black series fuel pump the most I seem to be able to get out of it is 12 psi I'm using the stock fuel lines could that be what's causing it if so what's an ideal size my motor will turn 10000 with no issues and has a 1050 demon series carb any ideas I have a Manuel sending unit in the tank

 

Holley Black should produce 14psi. If not, then possibly stock lines are restricting flow - Not just pressure, but also volume. If the pump is pulling fuel rather than pushing (i.e. rear fuel tank with pump mounted in the front of vehicle) this would also affect pump performance. If you're running a Demon carb then you should only need less than 9psi through a regulator. Set your regulator per carb instructions, then check your fuel pressure at WOT to make sure it doesn't drop. You might be OK if the motor is NA. If you want to be safe, mount the pump at the tank and run 1/2" hard line forward. Keep in mind requirements for return lines depending on your setup.

 

I have the fuel pump at the front by my motor and it's drawing from the tank and it's a thirsty big block we dynod it using 16 psi for maxing performance do u think if I use a inline fuel pump about halfway it'd help as well

 

electric pumps work better as pushers, not pullers. put the pump as close to the tank as possible and that should help get more flow. did you sump the tank or are you running through the stock sender and lines? if using stock, did you remove the in tank pump if it had one?

 

It's got the stock sending unit no pump in the tank and I'm using the stock lines

 

then you shouldnt have a problem. id still highly suggest moving the pump close to the tank

 

I'll try moving the pump halfway and see what happens

 

If it had 16psi on the dyno, are you using a regulator between the pump and the carb? The carb is optimized to run on less pressure, and so you would need to reduce the fuel pressure to about 6psi and then jet accordingly.

 

agreed, if its carbed, 16psi at the carb is WAY too much

 

I using a hokey regulator as well that's what I'm running. My return from and the carb has been rejected etc the shop built my carb as well

 

A Holley regulator

 

what psi are you getting to the carb?

 

I'm getting 12 to the carb and it's just seems to tickle in a sense not spray if I floor it it falls on its face and wants to DIEbut 3/4 throttle and I can spin the tires and whip your head back it's in time the shop said its fuel issues any ideas

 

It wants to die when you floor it because the mechanical secondaries are opening and theres way too much fuel (too rich), probably because of the fuel pressure. The regulator needs to be adjusted so that correct pressure is being delivered to the carb. (See page 7 of the manual in the link.) Then you can jet and make any other carb adjustments needed. Among other things, high fuel pressure will put float adjustment out of whack, and the carb will never work properly.


http://www.barrygrant.com/frombarryg...0manual-08.pdf

 

5-6psi is what you need for a carb, 12 is still way to much.