There is no shortage of Magnum cores. Magnum engines are plentiful in the junk yards. Here in Michigan we have lots of Magnum equipped trucks, vans, Durangos, and Dakotas cycling through the yards on a regular basis. Even the early year trucks that still have LA oiling come through the yards on a regular basis. If any shop wanted Magnum blocks they can work with the parts locator network and have all the Magnums they want. The real issue is supply and demand. There is lots of supply, but not as much demand from people willing to pony up the price of new crate engine. If you have 2000 guys begging for Chevy engines to be built and 200 guys begging for Mopar engines, which one takes priority?