If it has aluminum heads,and depending on the Dcr, here's what I would try;
What I would be trying to do is reduce the chamber temperature, to some level below the detonation threshold.
Then once it is detonation-free, I would start increasing the loading and increasing the coolant temp.
The very first thing is the cooling system.I would install a 160stat.I would make sure the cooling system can maintain a maximum of 180*F. If it cannot run a stable temperature, at or below 180*F,I would not proceed until it can. I would ensure the engine gets only fresh cold air.
I would disconnect the secondaries,and disconnect the Vcan(for now). I would run 3.55s or better, and a 2800TC or better,and a stand-alone tranny cooler.And I would run tires that fit in the stock tubs;ie 28 or shorter.
Then I would try it. with the 91
If detonation persists, I would figure out how little timing the engine will accept at about every 500 rpm,from 1500 to 4500, and build a timing curve to get it done. I would probably start with resetting the initial timing to 14/16*and the power-timing to 32*@ 4000. I might install a small Vcan, say 10*, and run it direct to manifold vacuum. That way the idle timing would be 24 to 26*. These are some of the things I would try.
Once the engine is running detonation-free, I would bring the secondaries back on line, and try it.
Then increase the minimum engine running temp with a 180stat
Then try to bring the power-timing in a little earlier.
If you have a 12.2 engine, there's a good chance you already have most of these elements,like; the gears,TC,Cooler,and street tires. So it shouldn't be too difficult to get the rest. If you don't have fresh air, pull the hood off for now, if it is legal for you to do so.
If you have a pretty big cam,(which would decrease the Dcr), you may get this to work,with some powerloss.
If you have a small cam,HaH! (with accompanying high Dcr),this is a probably,no-win situation.
I ran 10.7Scr,8.2Dcr with an aluminum headed 367, on 87E10 for over 14 years and 100,000 miles. Some of those miles were at 11.2/8.7, also on 87E10. I ran full timing of32 to 34, and loading was a non-issue. Except for the very first year,I have always run it at 200*F or a bit better.I did have to put fresh-air on it. At 11.2, I delayed my power-timing to 3600.This combo went 93 in the 1/8th and doing the math on that, makes about 420hp.
And like said, if all this fails, there's always water/meth injection.And if you go this way, you can put everything back where you found it.
EDIT
Hold on there;I just noticed on your home page, that you are running about 600hp; so then you're probably running a stroker.And Red Deere is probably a little higher than Winnipeg,Where I am(900ft) And you have got to be running a pretty big cam, so your ICA might be 70 to 76 *, Making your Dcr a hair under 9/1. If I'm close, then you are very close to being able to run 91 exactly as you are. Especially if your car is really light, and already has fresh air,and if you stay out of the secondaries.
So, then new plan. Block the secondaries closed,delay your power-timing to somewhere after 3600, Keep the engine cool,and road test it on pure 91.
So forget about all that earlier stuff.If it takes it try either bringing the timing in a little earlier OR see if she will take some secondary; but not both at the same time.
