Check pedal to IP throttle linkage and make sure you have good fuel supply. You might not have enough fuel to rev properly to the governor limit under load. If there’s a safe way to test, it should go to 105-110mph with a couple of people aboard.

My ‘83 SD would get to 85mph with AC relatively quickly and be happy there for miles. I would have liked it to get off the line with more spirit but I didn’t miss the 603 for freeway cruising.

Sixto
98 E320s sedan and wagon