Duke,
I too had my first 460 motor that crapped after about 300 miles. I found a guy named Arron Johnson at Bad Ass Racing that built me the 460 motor (actually a 522 now) I have now and it is truly awesome.
Arron also has a complete line of power building videos that he has prepared and distributed. I don't know of anyone who knows more about engines than him.
He also builds and ships motors all over the country. Check his web site out at
www.badassracing.com
Mike