here's the easy button if your call to PRW doesn't pan out:
https://www.manciniracing.com/crshroarmads.html
note, that's a crane part number... lookie here:
https://www.summitracing.com/parts/crn-99802-16
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:
http://bradanderson.com/product/1-ba-3-adjuster-screw-38-x-5161-450-oal/