What happened to all the Mopar Performance castings and materials ?

After I bought that NOS 440 short block, I then needed Heads. It seems like everybody had NOS 452's and were selling them for about $200 a set bare. 1 set I bought was a 452 and the other head was a stage 4. I approached the vendor at a swap meet and he said he checked all heads before he sent them out. Well at the time he was the only one I bought NOS heads from so I couldn't have made the story up. Fortunately somebody was looking for 1 stage 4 head and I was able to send it to him. Shipping was $80 to WI.