[Dr. Sivana]

Premium fuel would not help a 318 because it was never built with high enough compression that it would ping without premium fuel.

I had a '79 Dodge Diplomat and an '89 Chrysler 5th Avenue (almost the same car! the '89 was the last Mopar automotive V-8) for many year. If you didn't give it premium, it would knock. Maybe the pre-smog control ones were set differently.

[OA5599]

Oh I get it now. You had two “lean burn” era 318s. They were low compression (about 8.5:1) but they starved them of fuel with a super lean mixture and advanced the timing like crazy to the point even lower compression engines would ping from all that heat. So yes, you’re absolutely right. Premium fuel and under-performance.

My 318 was in an older van before lean burn, and my similar 360 was in a pickup truck without lean burn despite being right in the middle of that phase. Never had a malaise era car with those stupid federally mandated mpg targets.

Sorry to doubt you!