Paul is correct, ALL the 'new replacement' dual action mechanical fuel pumps come from china and are Defective in the box.
It doesn't matter which vendor is selling them. There has apparently been only one off-shore manufacturer / supplier for the last 5 or 6 years. For some strange reason parts retailers are still offering the defective pumps for sale.
With the relatively low volume demand for a 70-ish year old part all the quality manufacturing sources for them no longer exist.
Same with the rebuild kits, not available except for this possible source.
https://www.then-now-auto.com/product-category/fuel-pump-kits/
These two rebuilders could be creating their own 'kits', not sure.
https://agrebuilders.com/
https://www.facebook.com/profile.php?id=100064792812788
Terrill Machine Inc.
1000 CR 454, De Leon, Texas
(254) 893-2610
Email:
terrillmachine@yahoo.com
These three T-Bird restorers / parts suppliers offer a rebuilding service: Prestige, Hills, or Casco. There may be more but I'm not currently aware of them.
The chinese fuel pumps can be easily spotted by their Phillips head screws, example photo below.
Their very poor build quality means rebuilders won't accept them as a core.