Came off of a 350 out of a '98 Chevy Pickup. They are casting #12558062, if you know anything about vortec heads, these are the same as the 906's just with a different casting #, GM even calls them by the same part #. They have a little over 80000 miles on them. I'm looking for around $275 out of them, I can sell them on ebay for like $325, but i dont feel like dealing with it.
If you are interested PM for pics or come by and see them.
here is some info about them
Vortec Heads