Good cheap 383 builds??

I don't believe hardened seats are a neccesity. Exhaust valve seat recession seemed to be a much bigger problem with GM stuff. If you are not careful you can end up with more money invested in a set of 516s than they are worth. If you are working with a tight budget , just put new springs on and run them as is. New valves, guides, hardened seats, valve job, etc, will cost several hundred dollars. IMO, you should start with a better head if you are going to be spending some money. 516s will NOT flow what a 915 or 906 will: http://www.moparts.org/Tech/Archive/bb/62.html