Daniel......which spark plug part number are u using?
Do you know if they are the right heat range?
Do you know how far they protrude into the combustion chamber?
Plugs are available in regular reach as well as long-reach.....maybe u have the long version. Look up plug manufacturer charts and cross-reference charts.
Call up the head manufacturer to get plug recommendation.
Try side-gapped plugs to minimize protrusion into chamber. Too much protrusion will create a hot spot because the ground electrode stays too hot and promotes "dieselling" which is also pinging. Auminum heads would draw enough heat from the plugs as not to be an issue if heat range is correct but not if protrusion is too much.
Colder heat range plugs are fatter in the center electrode thereby conducting heat back into coolant more quickly.
http://www.ngk-sparkplugs.jp/english...q13/index.html
As ScottI says, octane rating is critical. Octane booster is available as a concentrated additive. Try a half tank full.
13* static sounds way high to me. 10*_32* should take you out of the twilight zone......again ask the head manufacturer.