It's a Poncho, so check oout the poncho sites. I think Kanter may have some stuff but Egge is probably your best bet. Did you score the motor off ebay I sent you?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33615&item=2434227093

http://www.1colorado.net/1957-pontiac/carparts.htm

http://www.vehicleservice.co.za/class/1955pontiac/pages/00000008.htm