Hy Perro, is there any chance that there are two gaskets on top of the filter, in other words is there a gasket stuck up in the filter mount in the block? If the engine was rebuilt that long ago, the relief valve in the oil pump cover could be stuck in place, or the bypass valve could be stuck, or it could have been plugged by the builder. Do you have an oil pressure gauge in place, what was it reading when the engine was running?
