This isn’t stock, anyone identify this

The problem with the OE hold downs is the lack of bearing area for the rocker. Stock cams and springs it’s not usually an issue but quicker lobes and higher spring loads and the OE hold downs will chew up the rocker.
Well them there rockers don't look too far from the OEM application. The aftermarket rocker shaft hold down surely can not hurt. Thanks for for the info concerning higher spring loads.