I know you guys are going to beat me on the noggin for asking this question again, but I'm a slow learner!
I built my LA 360 with open-chamber "J" heads and too high a compression ratio (10.5:1), back when you could buy better gas, and now it detonates badly on 91 octane no matter what I do. I am sure this is because the J heads don't have enough quench. If I changed to a closed-chamber head, I'd get more quench, right?
Can anybody suggest one? Thanks a lot.