Im thinking about changing from my edlebrock 750 to either a 650 or 750 holley double pumper because the edlebrock's throttle response is awful especially at 2k or below. Has anyone noticed any hp gains from doing the swap I'm curious to know what the difference in power would be.

 

Should not be noticable.

A properly tuned and adjusted edelbrock carb should work as well as a holley.

Most including holley do not recommend double pumpers for heavy, street cars.

One of the mags did a comaprison of many carbs recently, they were all very close.

Download the edelbrock tuning guide and get it dialed in.

 

For a mild 383....650 is plenty. But i agree...fix what you got. May need different air bleeds and jets...lean it out.

Also a good time to dbl check timing if its bad down low...just to be safe.

 

I'll try sticking with the edlebrock for now and play with it, but honestly I think 750 is a little too big either way to get good intake velocity at the rpms I will ever see. Hey if it saves me money I'll give it a shot.
The timing was check a while ago when I did the flywheel and everything was good, cant remember any numbers but nothing that made me think it was off. The car starts and idles alright too.

 

I had a similar problem with a Holley carb, poor response below 2K when I first got it running, and looking into it I had the idle adjust too far exposing too much of the idle transfer slot below the throttle blades causing a bog. Not saying that is your problem but it is in the tuning.