See post#49here's the easy button if your call to PRW doesn't pan out:
note, that's a crane part number... lookie here:
Crane Cams 99802-16 Crane Shaft-Type Rocker Arm Adjusting Screws | Summit Racing
Free Shipping - Crane Shaft-Type Rocker Arm Adjusting Screws with qualifying orders of $109. Shop Rocker Arm Screws at Summit Racing.www.summitracing.com
so you may be able to snoop around a bit an unearth some on a dusty shelf or ebay
or you could start here and DIY the rest:
1-BA 3 ADJUSTER SCREW 3/8″ X 5/16″,1.450″ OAL | Brad Anderson Enterprises
» 1-BA 3 ADJUSTER SCREW 3/8″ X 5/16″,1.450″ OAL | The Choice of Championsbradanderson.com