427 S/O Some aluminium rocker are made from better material than others. You get what you pay for. The questions I have for you are this, How big a cam is in the motor? What is the MAX rpm you are turning? What valve springs are on the heads? Do you have limiters for oiling the rocker shaft assemblies? Under STOCK, NORMAL DRIVING these rocker should last 30-50K miles without any problem. High rpm running,missing shifts, floating the valve train large lift cams, and heavy duty valve springs will all help in breaking the rockers, bending pushrods, or lifters that collapse. If you go to the FE forum and search rocker failures you will find the same thing that happened to you.
IMO those rockers should not be used on any camshaft bigger than a .550" lift with stock spec valve springs and a 6,000 rpm limit to the motor. If one rocker is now broken the rest are sure to follow. I see the bronze bushing are still intacked on the shaft. Get the Ersons and forget have any more problem. Used nothing less than an ..080" orfice to limit the
oil in the top end of the motor. The valve spring and rockers do need alot of
oil to keep them cool and control the heat or friction of the parts. Rick L. Ps I run a hydro roller cam and lifters. I use the pushrod oiling for my rockers also even though this is not needed for a street motor. I race most of the time. Too much
oil will not hurt anything. Just overfill the motor by 1 quart for safety.