we run reinforced stock 342 rockers. Dual springs from Jimbo. SS valves. Dyno cam. My son figured a way to do this with 3/4 in 4130 tubing. Cut and fit. Then TIG weld with SS rod on both sides where they tend to split. Ran last time to 7800 RPMs. No Issues. The Rocker Arm Geometry must B correct! The design ratio is apprx 1.5 to 1.0 We also instd 1/4-20 heli-coils. and used Gr 8 SHCS to hold the Trunions [trunion hole must B opened to 1/4 in Also-use a Carbide drill-MSC] down to the head on I and X. If anything [block-head ] is Milled you will have to use custom length pushrods [We use a Comp Cams make them yourself kit] hope this helps IF you have problems in the future