Ayuh,..... It's a Chevy motor, 'n I only use AC Delco's in Chevy motors,......
The MR43T for motors up to '95, 'n the MR43TLS in the '96, 'n later motors,....
The AC Delco marine spark plugs are Not Plated, they're an alloy body, 'n don't rust into the heads,.....
That's where the "M" in...