Rick:


**Is pre-ignition the "exact same phenomenon" as auto-ignition, but self-initiated before the spark event?**

No.

**Does pre-ignition "need" a "glowing ember" or can it be induced by pressure & temp alone?**

It needs a flash point like a spark plug that's glowing or a helicoil tang.
 
**is it possible to have both pre-ignition and detonation?**

Yes. 
 
**Does detonation tend to be aggravated or lessened if you were to turn one of the mags off?**

Yes, that will frequently stop the detonation.

**I have heard (OWT?) about bore size being a contributing factor to detonation before, but I’ve never really understood the mechanism behind why bore size would aggravate detonation.**

One would think that bore size would affect the time it takes for the flame front to cross the cylinder and require a longer latency to retard any detonation tendency. I haven't studied that in Taylor, but my guess is that it's a minor factor.
 
**Has George done any testing with more than two spark plugs on the large bore engines? **

No, I don't think so.

Walter