ok so as it stands, the Z has no ignition cylinder, just the switch. i found this on ebay and was wondering if it was worth it....
http://cgi.ebay.com/ebaymotors/Datsun-240z-260z-280z-1970-1978-Ignition-Switch_W0QQcmdZViewItemQQcategoryZ6763QQihZ017QQitemZ270214544438QQrdZ1QQsspagenameZWDVW