Compression specs are usually given using the smallest chamber and also several other variables. If you run a compression test, we can get very close with a decent distributor curve I just bet will take care of the detonation.
I can’t get compression numbers just yet as I have some reassembly work to do yet. But I can get that done early next week.I
I did plot my curve and recall it being very gradual to soften the detonation. I think I was all in like at 3500. This along with a slight retard did stop the detonation. But the cost trade off is performance.