...as in an LA block. The rocker shaft oiling comes from the deck on LAs, so if you want it to function in a magnum block (which aren't drilled for that provision), you need to either drill a hole from the deck down through the casting into the #2 and #4 cam bearings (#2 on the left bank, #4 on the right bank) perfectly, and use LA block cam bearings and LA drilled cam (Magnums don't have the oiling holes in those journals to facilitate oiling rocker shaft oiling) that provision won't exist.
