holley 750 dp question

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Early a body

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Hey everyone,

I have a peculiar issue I was wondering if anyone has a solution

I have a 408 4 speed . I had an edelbrock 750 on it then switched to a 750 dp. The DP is about 2 years old. The DP is much stronger from a dead stop. Accelerated hard . But when I have it floored out it seems to slow the acceleration compared to the edelbrock. it feels like I need to add another carb to get the top end to continue the acceleration as fast as it is when at a dead stop. . I do not have this problem with he edelbrock . I really like the holley for the low end performance but i am disappointed with the top end performance.

I have messed with the nozzles and the jets but nothing seems to help. The car actually performs better with the holley right out of the box vs messing with anything on it.

I may go ahead and but another new edelbrock to see if there is any difference in the bottom end vs my old edelbrock.
 
Run the Holley straight out of the box. What elevation do you live at?

an air fuel meter is your best friend
 
Early a body said:
But when I have it floored out it seems to slow the acceleration compared to the edelbrock.
Click to expand...
In what gear or what speed?
Installed with no other changes?
with same fuel system?
same air cleaner as the Eddie?
Similar ambient temperature?
On same road?
Have you done any timed runs with both?
 
In this day and age there are two devices that are nearly a must-have for the guy with no dyno. One is an AFR meter and hopefully a logging system built in. The second is a "performance meter" I have an old G-tech. I haven't kept up with what is available, but "I bet" the newer ones blow my old one away. Generally these sort of devices give you acelleration over time, speed, RPM and log it so you can see after the fact.

Meanwhile, as someone else noted, "Read the plugs." What does your rear view mirror "say?" Is there visible black smoke? Way too rich/ way too lean?

And don't forget the power valve...................
 
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