Got to be some kind of market. 73 spindles are hard to find because they are one year only but you can always find a 69 to 72. The only reason nobody uses the early spindle is the 2 piece rotor is 3X the price of a unicast IF you can get them. That being said you won't get rich but you should be able to package up a set of sleeves and the seals for an attractive $$ and still make a small profit. You could add this to your disc brake conversion kits using factory parts list. C-bodies are going to be the next big thing. (no pun intended)

Kevin