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What spark plugs are you running, brand and part #? I had a low compression(8.5 to 1 actaul) I/O drive boat motor that would ping using a Champion J12Y spark plug set but wouldn't ping using the next lower heat range, J11Y I would try the next colder heat range spark plugs The last iron headed 440 motor I tuned until it ping didn't like any total timing above 36 degrees on Oreogon non ethanol 91 octane pump swill I would put the total timing at 34 degrees revved up and readjust the intial to get between 14 and 18 BTDC I like and use really weak advance springs in my distributors so the total timing is all in by 2000 RPM My converters are a lot looser than that at WOT, they will flash to 4400 RPM or higher There very similar driving on the street to a stock Mopar 11 inch converter at light part throttle pressures below 3000 RPM also

I am using NGK xr5s and have been for years. This problem was non existent with the auto and loose vert. With the manual the engine is getting load now at 2-3000rpm and that's where the problem start raring its ugly head, that and pure pump swill. If I could just run 5 gallons of 110 per tank and not kill my o2 sensor, this thread wouldn't exist. When the weather let's up I'm gonna try to keep my initial as is,set total to 34-35 and swap out one spring for the next heavier. I have the black bushing left to narrow the advance down to I think 18 degrees total mechanical to try.

Mopar to the bone!!!