IN THE PAST USING THE HEATED 02 WITH MUCH SUCCESS
EACH TIME I BUY ONE IT HAS A DIFFERENT # I WONDER IF ALL THREE WIRE O2'S ARE THE SAME. I HAVE USED
0 258 003 950,AFS74 AND 0 258 003 077. THEY WORK GREAT WITH RACE GAS THAT'S ALL I CAN SAY
FRANK
The numbers starting with "0 258" are obviously Bosch numbers, while the AFS 74 is a AC Delco part. They may not be identical, but all are of good quality and I'm not aware of any issues in using Bosch O2 sensors.
I have wired up a connector to use the AFS 74 and generally get replacements at a GM dealer who offers a discount. Several such dealers are available online as well. See http://www.gnttype.org/vendors/gmparts.html for some contact info.