Reply to "Backfiring engine..."

Limiting a Cleveland to 28 degrees total advance makes no sense at all. It is taking the crispness out of the throttle for sure, as well as any kind of a top end at all.

These engines were designed to perform on 34 to 36 degrees of advance. You can't re-invent the wheel.

28 degrees is simply a statement about the octane rating of the fuel. Sounds like 89 (regular grade here) to me? I might expect this with a supercharger possibly.

The only way you would have to restrict ignition advance because of camshaft timing is if you are not running enough cam, i.e., too short of a duration.

Longer duration would reduce the tendency to detonate, not increase it.

In fact there are longer duration camshafts that have longer duration on the exhaust then the intake in order to reduce cylinder pressure by blowing some out of the exhaust.

34 total from 36 is the only compromise you should make. If you are running only 28, why bother to drive the thing at all? To me, that would be like driving a diesel.