That was the date on the ProMaxx site. The SBM heads have all been out of stock for several months. Must be expecting a shipment.
He quoted me $800 to convert my regular 171's to the CNC Shocker 185 level with 2.08 intake valves. That seems pretty reasonable, but I can't use that flow at the moment. Going to give it some serious thought when/if a 4" crank goes in, down the road.