Alright folks, here it is, I was reading the performance tuning book by Alexander Graham Bell, and I have the scoop, from his own mouth, on why a straight plug engine is almost ALWAYS better than an angle plug for performance. He writes "Quiescent chamber with offset spark plug end gases detonate." To translate the words of this Confucius of two strokes this means that when your plug is angled so it is to one side of the dome, it takes longer for the gases on the farthest side to detonate, so there is uneven detonation. What he says about the straight plug is "squish chamber with central spark plug ignition flame advances smoothly." This smooth advancing of the flame kernel means a more even burn and a more rapid and efficient use of the energy in the fuel. If you do choose to use a slant head you should NOT point the plug toward the carb side of the engine, this CAN lower performance and create hot spots. It is best to have the plug facing toward the exhaust so the flame kernel is directed toward leaving the engine. He does not recommend an angle plug, nor do I. Stick with the straight plug if it fits, if you need to use the angle remember, face it toward the exhaust. Let the comments begin!