Every car will be different. It will depend on the plugs you use, the fuel, etc. Do as Mr 5 0 said and advance it and drive up a hill in a high enough gear to really bog it down with the gas pedal floored. If you hear the pinging you've gone too far. It will be loud enough you will hear it assuming you don't have your radio cranked. That will be good enough to get the maximum amount of timing out of your car and be on the safe side if you back it off 2 degrees after it starts pinging.
But really, 16 degrees is plenty.
That 32 degrees of timing may be someone who is reading it without pulling the spout connector out and they are getting a bogus reading or they are quoting base timing before the computer takes over? They are probably actually getting around 12-14 degrees or so I'm guessing. I could be wrong as hell :P
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Gunning for 12's!
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