ol' Pinion head spring carlisle is coming bring a truck load of them you can sell them at 100 bucks a crack all day long for 5 days. I see what I would call a core going for 400 on ebay NOS with HEAVY shelf wear (read fallen off the shelf) 700-900 in fact a 100 bucks I would get one my self to return as the core for the one I had to buy.
http://www.carsatcarlisle.com/ Not trying to give you a hard time but I can get a repro for a 67 for $279