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I have a mild/medium built 454 with a Holley 750 DP, what should the pressure be at the carb, on the guage? I have an electric fuel pump, and a regulator, but don't know what pressure I should be at. The car starts to break up at about 4,750 when held full throttle from a start, like it's starving for fuel. Just swapped out the filter, also it only does it when it hits 3rd(T400) first and second wind through with no hesitation.

Thanks, Mike

[This message has been edited by 68SS454 (edited 12-06-2000).]
 

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The fuel pressure should be around 7 lbs at idle, never dropping below 5 when your foots in it. Any higher than 7 and the needle and seat won't close. When the car missfires with your foot in it or in 3rd, check your plugs. Is the white portion of the plug a very light shade of green? If so, the carb is to lean causing a "glazing" of the plugs. You may need to play with the jetting and power valve. Also, does it seem to bog when you put your foot in it? If so, the double pumper may be putting in more fuel than the car can use, waiting for the auto tranny to catch up. Just food for thought.
 

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Check your float levels. The fuel should be level with the bottom of the sight hole when idling. Your pressure may be low, emptying the bowl in the time it takes to go through the gears into 3rd. Check your vacuum at idle and make sure your power valve is appropriate. It should be rated about 1/2 of the idle vacuum, ie. 14" vacuum would give you a 65 or 70 sized power valve. My 700 DP had the float levels off significantly out of the box.
 
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