This is from a supplier posted on another FORUM -
Mechanical fuel pumps:
ALL new pumps as of 5 years ago are made overseas and are WAY over pressured for older carbs. Your choices are, have your old one rebuilt, or install a 1-4lb regulator.
We have dozens of folks a week calling in and they have blown the gaskets out of their carbs or have massive flooding.
ALL carbs that say NEW are from China or worse. Holley and Edelbrock have not made a carb in the US since 2000. Someone in China is using the Carter name on metric copies.
Pay thru the nose and use original carbs made here.
There is no quality left. If all these suppliers have to offer is CHI-COM junk they should mention it in their cataloging.
You will need to find an original core and have it re-done to modern specs.