Ok car is a 91' 350 TPI, timing is advanced to about 12 degrees on 93 octane. Runs great,but i wanna run 89. Everytime i have tried 89 i get a slight knock at about 4krpms and up. I have found retarding my distributor 1 degree to help but i like the low end power that the 12 degrees was giving me. So my question is this: what is the easiest way to remove some timing in the bin? Should i just remove it in the "Spark adv main" table at 90-100 map and 4k rpms and higher? or should i zero out the PE spark adv? any other ways?

 

I have a maf car but I zero out my PE timing and just adjust all my timing in my main spark table. So I guess you could lower timing in eighter area at high load over 4k. I'd pull 2* in the areas your getting knock.