Yep not much of a market.... the stock blocks, cranks, even rods in mopar sb & bb will handle 400 to 500hp just fine. Add good cranks, rods, with good machining and the sb and bb blocks can handle 600 to 800 hp for years and years!! That power level is fine for 90% of the mopar guys so why bother getting blocks out to that tiny 10% that really need the block.
Also I think this is something that Chrysler should make for it's racers for the sake of keeping there heritage and loyalty alive.