[Gach]

If it’s that sensitive my guess is you got something else going on. Really I ran mine with no issue on 93 octane, for years. Here’s a possibility and I’ve seen this a more then a few times. Some times your running what you think is total timing 32-36 degrees, but if there’s issues with the distributor, for example you put a time light on it and say at 1500 rpms. Time in while it says 32-36 degrees But ! You bring it up to say 3000-3500 and it keeps advancing, I’ve seen the advance up to 50 degrees. But you don’t know if that’s happening say your first instinct is kicking it back 10 degrees then it feels sluggish. Just something did you want to check out and make sure that it’s not advancing. Honestly I never had any issues with my 69 Grand Prix 428. Running on 93 octane. Just a thought something you might want to check out.