Originally Posted by rageworks

You can run an OD T77 plug, if you want a hotter plug.
A hot plug can mask an overly rich low speed needle
setting. I have seen this happen to a lot of people, when
it comes to tuning their engines. They end up with the
idle air gap too large, a rich low speed needle setting, a
hi speed needle set too lean and an engine that has a
mid-range bogging with flame outs.