408w bogging

I have a 408w in my 66 mustang. It goes fine except for when i hit it hard for a long pull it starts to bogg down when i get to about 80-90 mph. when i let the peddle off the floor it will come back after a second then be fine. I think it could be a lack of fuel. Like my pump isnt keeping up. I have a generic inline electric pump. 7-9 psi. Any help would be great. I cant drag it if it cuts out at 80.[img]/phpBB/images/smiles/icon_bicker.gif[/img]
Oh i also dont know if my secondaries are opening, i have a holley 750 vacuum secondaries. its fairly new. Any tricks to help figure it out??
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welcome to the board.
I use to have a holly red on mine when i first put it togethere. I could watch the fuel pressure drop on the gage. It would also die out at higher rpms also. then i put a holly black in it and problem went a way. Sounds like you have same thing going.
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I think its the pump too
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my fuel lines are stock, so i think they are 1/4 in. Ive been thinking if i go up to a 3/8 in that could fix it. i also decided to fix my vacuum secondaries problem by going to a demon double pumper.