Honesty moment here, I have never heard of that on gas engines haha.
Stick around- - - - -you might actually learn something if you drop the attitude case. Ed has probably forgotten more about stovebolt engines in general than you will be able to learn in the next year or two. Most industrial engines like the 292 Chevy and the Ford 300 6 cylinder have optional parts available for offroad applications, and Propane-fueled engines are used a lot for irrigation pumps, generators, and farm equipment. Since Propane is approximately 110 octane, compression ratios in the 11:1 range are not uncommon on engines running on straight Propane, not in a dual-fuel capacity. When I was in charge of the maintenance shop for a sand, gravel, and concrete producer, virtually every spark-ignition engine we had ran on Propane, and most of them were set up for high compression.
Jerry
