I'll tell you one thing. I have been looking for a long time. If you really want one, you are not going to find one used. Call Callies and get on the list. Right now you will be on a 14 week waiting list and they are the only one you can get a crank from if you want one that big. The only other option you have is to get one from sonny bryant but your looking at $3200.00 for a crank and its still 12 weeks away. Trust me I have already done all the homework. I got my crank on order from Callies and its still 10 weeks away. It will cost you $1805.00 plus the shipping from Callies for their Magnum series. Call them 1-419-435-2711
I can give you a number of a guy in canada that has a bryant crank that is a 5.600 stroke for a 4.840 bore space if you like. PM me for some info.