Fuel pressure dropping while driving and under acceleration to zero at idle runs 4 lb electric Blue

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Thanks for all the replies. When I pulled the supply off of the sending unit it was flowing out free flowing full stream like you had to faucet turned on. I just can't believe that it could be this hard to figure out. People's been running electric fuel pumps for years. Without seeing it. It's hard to diagnose I know.... Are these holley blue fuel pumps not designed for a 3/8 sending unit and two filters. A 100 micron and a 40 micron. All new 3/8 fuel line to the regulator.... Again, I appreciate all of the replies. Just trying to get it through my thick head lol
 
I had a question with the Mallory 250 pump. It says if you take apart or disassemble the unit and put it back together to test the bypass pressure and adjust it between 13 and 18 PSI. How would I do that. Do I deadhead the regulator with a gauge and set the regulator or the? I'm sorry the bypass on the pump to 13 lb
 
Deadhead the pump. Block the outlet port with a gauge. Loosen the jam nut (1) in the diagram and adjust the adjuster (2) in the diagram until the gauge reads what you want. Mallory says between 13-20 psi
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TT5.9mag said:
Deadhead the pump. Block the outlet port with a gauge. Loosen the jam nut (1) in the diagram and adjust the adjuster (2) in the diagram until the gauge reads what you want. Mallory says between 13-20 psi
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So what do you think? I would say that I'm only going to run probably four and a half or five on my regulator. Going to the two Carter competition series carburetors.. What should I set the bypass for on the Mallory 250 to be safe
 
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So new update. I hate to admit this but after all this trouble and all the good advice you guys give which I have taken. Turns out my 40 micron stainless steel filter is plugged which was the first thing I checked and it seemed clear and it seemed like it looked good but I never really blew through it until today. It was stopped up. So I installed a new filter and with the original blue fuel pump. All's right with the world. Thanks for all the help. So now I've got a Mallory 250 fuel pump with a new armature and bearings will be for sale lol

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I LOVED my 250 Mallory. 9s with a n/a small block. The motor I've got at the moment will be fine with a trick flow 150, so the 250 is on my shelf..... for now.
 
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