John,
I have it in my notes that a Chevrolet part # 20046147 25d3 pin will work. You need to ream the holes to get the new pin to fit and they need to be cut to length. Some auto supply stores also carry replacement pins (HELP! brand) so you could look there too.
Another option is to buy a used (but not too used!) hinge set from suppliers but that will be far more $$.
Cheers,
John