Derek, I put another full 16oz of Davis Plane Fuel through my .65 conversion today. I used a more suitable prop and took my time to make sure I got it optimum.

OS LA .65 blue
Newer Davis head with annular fins.
Fuel==Davis Plane Fuel for bushing engines
Prop==Bolly 13.5x8
RPM about 50 rpm below peak 9,250
Idle 1750 and slightly burbly

Clean throttling and very smooth.

I took the fuel level right to slurping bubbles and it simply quit when there was no more fuel, imagine that.

Today I ran a Fox Eagle IV with the Bolly 13.5x8, it doesn't match the LA .65 for power. In the picture it's truning about 8.000

Fox Eagle IV .60 ringed
DDD conversion head
Fuel===Davis ABC mix
Prop Bolly 13.5x8
RPM=====8,450

I have an older but in better shape Eagle III .60 I will run tomorrow. And then a PAW .60