From Bill at PRW
"Hello Steve,
PRW Mopar ball end and cup end adjusters are 7/16”-20 designed for PRW Rocker Arms with 5/16” ball or cup end pushrods. If you are looking for 3/8”-24 Mopar OEM Ball-Style Adjuster Screws, PRW does not have those to fit your application.
We do have strong lightweight Valve Lash Lock Nuts in 3/8”-24 (PRW PN: 1004502). These are available for your application and others that use 3/8”-24 adjusters. All PRW fasteners are SCM-4135 or 4140 alloy steel that are higher tensile strength than Grade 8.
I checked a few online resources and the parts you are looking for are not readily available from standard sources."