I fought with a Holley 650 carb for months trying to get it to run right, even paying to have it professionally rebuilt and tuned. Spent a lot of $$$ on jets, floats re-build kits ,etc. Never ever did it run right. The guy I gave it to, a die hard Holley guy, still is messing with it
I bought a Edlebrock, out of the box it ran. After just changing the rods and springs once, the car ran better than it ever had with the Holley. A few more minor tweaks and it performs thru the whole power band.
Get a manual for your carb model from Edlebrock, they sent me a new one at no charge(knocked over a can of
oil paint on mine). Study the manual, it pretty much walks you thru the whole process.
If you still have questions then call their Tech line:
1-800-416-8628 from 7:00am to 5:00pm, Monday-Friday, PST.
Everyone I've spoken with there was quite knowledgeable and walked me thru what ever problem I had, recommended part #'s, etc. This was not just on the carb either.
Their Tech people were a whole lot more helpful than anyone I got at Holley Tach line.