[Jerry in Shasta]

I have a LSH I It pings/detonates at 10 degrees advance light acceleration on 103 octane fuel.



I have soften all the share machining corners an smoothed out the chambers, still pings badly to the point that it is unusable.


It was given to me by a very knowledgeable Model A guy that could make it work either



Any ideas?? Sorry I don't own a boat.
JB