I purchased one of those "Deezil" engines from GHS when I was in highschool. Initially, I could not make it run. Several years later, after learning more about model engines and successfully using an OS .15 diesel engine in a RC pylon racer I was able to start the Deezil. It barely ran and as I remember it it was very touchy on the compression and needle vavle adjustments. Prop used was probably a 9x6 or maybe a 10x6.
Anyway this thread was an interesting read and brought back some memories from the 50,s for me.

John
Scottsdale, Az