Ok I did a search and came up blank... trying to get my 302 sbe x headed carb engine to like me... I had 55° of timing in it my first ever pass on accident I couldn’t see the mark and thought it was 30° so I took it to 30 still stumbled off the line next two passes. Got it home. I put a fresh plug in each side before every pass. I took it down to 20° of timing to see if it like it better than 30° well I revved it and it went quiet and then shot a nice 4’ flame out the carb. Never seen retarded timing do that only too much advance... it’s a vic jr single plane intake 750 Barry grant (I know it’s too big I’m working on getting a 650 main body) I’m on 100LL fuel. Planning on a 100hp single stage plate. Plugs had timing mark was about 1/16” away from the threads which is why I want to pull more timing. Is 20° too retarded? Would 25-26° be better? Oh yeah I forgot to mention the distributor is locked.