I also recently had the opportunity to purchase a new R3 with a new crank. He also had one of the later Mopar racing heads and I saw another head on ebay. I was really wanting a small block Mopar that could turn some serious rpm. After reading about all the special parts required, and how hard they are to find, I think I came to my better senses.
After looking for info about these blocks, I just realized the block I was offered was an R5 with the open deck. That seemed really strange to me when I was looking at it. Now I wonder what all special parts that would need.