I've been very happy with investment cast stainless Crowers on my engines. I don't remember the part number but they are intended for 250/292 Chevy with 3/8 rocker studs.
I do recommend upgrade to name brand shouldered screw-in studs. The BBC rockers use 7/16 studs so be sure to match up studs with rockers. And also, be sure to provide thread relief when machining your rocker stud boss. I've seen this step missed and the boss split by the last incomplete thread under the hex. Chamfer, counterbore, or hard washer all can be used for thread clearance.
