Fuel Pressure?

[Wet Dream]

I'm running the Edelbrock 750 mech secs ojn my 455 with a mechanical fuel pump. I usually cruise around 3000-3400 rpm and have 6-7psi. Its when I throttle more, the engine will pick up but then fall off a little and have to compensate with more throttle. The fuel pressure is reading 3psi at WOT. Is this enough or do I need to start looking into an electrical pump?

[Infomaniac]

What kind of mechanical pump?
This is suddenly happening? If not look the fuel system over really well for restrictions and look in the fuel pump and filter for debris, corrosion, etc.

[sanger rat]

You may just need more volume. Bigger lines may be all you need.

[396_WAYS_TO_SPIT]

You may just need more volume. Bigger lines may be all you need.
Thats what i was thinking....

[Wet Dream]

This has been going on since I changed the carb this spring. Its not a problem, but seemed a little weird that I would have to throttle a little more to make up for 50 to 100 rpms. Its not stumbling or anything like that. Oh, and the mech pump is the same type that came on any Olds, crank triggered. ;)

[Taylorman]

I had that same problem with an Edelbrock when i first bought my boat. Does it hesitate when the secondaries start to open? Thats what mine did. When you give it a little more gas it would clear up. I ended up changing to dual carbs and the problem went away. Heres my opinion on the cause. I read the Edelbrock manual front to back and i think you may need stiffer step up springs under the metering rods. If your somewhat familiar with how the Edelbrocks work you'll understand this. At idle, the vaccum pulls the metering rods down into the primary jets to restrict fuel flow. As rpms go up and vaccum goes down the reduced vaccum along with the step up springs allow the metering rods to move up out of the primary jets and allow more fuel flow. If they don't move up fast enough due to the spring being not stiff enough, you will not get enough fuel which may be causing your flat spot. So if you try a stiffer step up spring, that MAY fix your problem. That would also be a cheap and easy thing to test. 5 minutes to change the springs. Find out which springs are in your carb and put some stiffer ones.
While we are on the 455 subject, i just changed my intake to the new Victor with a Demon 850. Picked up 100 rpms. I had a tunnel ram with dual 600 E'brocks.
http://www2.***boat.com/image_center/data/500/161DCP_5518.JPG

[sanger rat]

Taylorman. Looks SWEET! Very clean looking set up.