Okay, so Joe threw up the bat signal, and it's subjective as to whether I'm batman or the Joker...either way I'll put my 2 pennies in.
First off, what I do when I order a chip is to ask for lower timing than what Eric would typically program, so for an alky chip I'll ask for 20/18 and from there I'll add timing as the engine responds or complains and leave it there.
Fueling is another issue and for another time.But the reason I ask for this is often in our 25 year old wiring there can be a blip of the 12Vs supplied to the ECM and that would reset the chip to it's default settings. Now, how I drive my car on the street and at the track is distinctly different and if the chip goes to default for some reason and I don't know that? then I'll be comfortable knowing I'm not going to push a gasket when I go WOT on a cool ,dense air, summer evening....but that's just me.
I'll address Shawn's issue later, but let's talk about detonation and pre-ignition, because they are 2 different things under the umbrella of "abnormal combustion".
Detonation happens AFTER the spark plug lights the mixture and a quickie explanation is that the plug sparks....the mixture begins to burn across the combustion chamber, ....heat and pressure begin to rise..... and for a variety of reasons the mixture at the other end of the combustion chamber spontaneously starts to burn and the two flame fronts begin to race toward one another...it is the sudden increase in cyl pressure that creates a resonance within the block and manifests as noise we hear as a knock or ringing and it is that noise that piezo electric knock sensor picks up and sends to the ESC module to be filtered by Hz and duration and as to whether it's real or to be ignored by and reacted to by the ECM.
So as the piston travels past TDC, the cylinder sees the point of peak cylinder pressure at 14* past TDC. So somewhere past ignition point and 14* ATDC the 2 pressure fronts collide and that is detonation....and is after the piston passes TDC. It is harmful but a little is not life threatening.....except in a boosted application...which is where we live, so I agree with Rob that the main bearings take the most abuse from detonation ,as the piston is forced harder downward on it's already downward stroke and our measly little cast cranks flex under the strain and couple that with cast 2 bolt caps??? well, it's not long till the babbit is worn and the copper layer is exposed on the bearing.
So, when you blow a HG it's a pretty safe bet that you hurt #2 and #3 bearing lower half(s)....to what extent? only an inspection will tell. Lots of guys blow HGs and replace them and never have an obvious bearing issue and that's great but my experience with many blown HGs has proven differently.
Now pre-ignition is just what it says, a start of the burn of the mixture before the spark plug lights it, and it can be from hot spots, to burnt exhaust valves, etc and an engine wont live but a couple seconds before it does catastrophic damage...that's a quick explanation but I really don't think it's part of this thread's discussion.
To Shawn's (Sp?) question? I agree that your FP is lagging and I'll also suggest that you put new valve springs in because it's been my experience that weak springs will cause some small detonation (real or false) at the big end of the track....yes, they begin to float and either cause mixture/combustion issues or just plain noise.
But It looks like your combo is pretty consistent at high 11's and that's not to shabby at all....you could add a degree or two in the 1/2 to help get you out of the hole, but I'd leave the 3/4 alone for now.
