AJ is right on. Something doesn’t add up. For a test you could not change a thing on it and pour in 10 gallons of 110 and see how it responds. It should run noticeably different. Is this a new problem or have you been dealing with it for 18 years?
well, originally i had JB welded the advance slots, then tried it, then took it back apart and filed them some, back and forth until i had it good as long as i used 91 or higher octane pump gas. This was with the mopar ECU. I also had it dialed back to 16 degrees BTDC. Since then i have done the GM HEI module conversion hiding it in the gutted mopar ECU and also installed one of the FBO plates and am in the process of getting it right. I find it like 20* initial better than the 16 but like i was saying, it detonates slightly when nailing it under 3500 rpm and figured the timing needed to be slowed down. I know it comes all in quickly with the spring i have in it. all in before 2200.