Both Crower and Comp Cams offer steel roller rockers that will fit the Chevy 194-292 series engines. Crower rockers are stainless steel, Comp Cams' rockers are 8650 Chromemoly steel. Unless you plan on changing the stud size from 3/8" to 7/16", order the part number for 3/8" studs. Crower part# is 73629-12, and Comp Cams part# is 1629-12. An interesting side note is that the rockers with 3/8" studs are listed for Chevy 348-409 motors, and the rockers with 7/16" studs size are listed for 396-454 BBC's. Apparently GM used the same rocker geometry for both engine series as well as the late model six cylinder motors, the only difference was the stud size.
Besides Tom, you could get either brand of rockers from Summit Racing, JEG'S, or the manufacturer's websites. I'd try Tom first, since he's one of us and there probably isn't much difference in prices for any of the retailers.
