ramrod;c-145970 wroteIf ping, check ignition timing. There should be no ping even on 91 octane unleaded. The higher the octane the slower the burn, especially if the engine in question doesn't take or need high octane. High octane used in an engine that doesn't benefit from it will introduce less response, so it's a backwards step
From memory, the manual for 81-82 with that particular B23E (405 head, K cam, 10:1) specifies 96RON minimum, and 10°± 2° base timing, which is set with vacuum advance disconnected.