Evan, the data was found refering to a 6 cylinder cht that we had in our pawnee. Also reconfirmed on a 200hp Stinson also with 6 position cht. Doubt away, the technique does work, been using it for 30 years, have never cracked a cylinder. And regarding your bird dog (glorified 170) venting fuel, I hope your not towing with topped off tanks, that extra weight costs you time and money in the long haul unless where you operate doesn't have handy fuel available. We always operated with 3/4 tanks but note we were flying in extreme density altitude conditions.