185 does not sound too high... And 2.6 motors are generaly tolerant to CR increases. I have run them at 9.5 to 1 with no issue with 92 octane fuel. That took a good head shave to get there, more than any shop would knowingly do.

I would make sure the vacum advance is conencted to the correct port and that the EGR is working. Also make sure the advance mechanisms in the dist works ok. No broken springs, worn shafts ect.

I have gotten a 185 PSI reading and still run 10 PSI boost and not gotten detonation.

Also make sure you dont have a lean cylinder or a hot spot.

Kevin