Follow Shaffer's advice.
All the pumps you buy new today are absolute garbage. They're all made in China regardless of brand name. They will fail soon after installation if they even function at all out of the box.
Send your original pump to Then and Now Automotive or purchase one of the NOS pumps online and send that to be rebuilt. Calling them on the phone is the best method of contact. They're website is not very helpful.
They did my original pump 10,000 miles ago after 2 new pumps failed. One would not pump a single drop right after installation. The requisite fuel pressure for the 1950 216 is 2-4psi. My pressure is 2.5psi at the carburetor.
Then and Now Automotive
447 Washington St
Weymouth, Ma 02188
Ph: 781.335.8860
Fax: 781.335.1925
https://www.thenandnowautomotive.com/