were made of pot metal and they rotted and broke off in the intake manifold all the time. You had to drill the broken part out and rethread the manifold. Huge pain in the ass. The updated part was steel and we never had problems with those, but GM parts kept sending out the shxtty pot metal ones unless you specified the updated part. To this day I still see the pot metal ones being installed. They must have made millions of them and nobody who knows better wants them.