While there is a "best" glide rate or speed based on each aircraft configuration, these aircraft were designed to be flown with power ON unlike a glider. Best glide rate wasn't high on the performance needs list. If the engine quits, push the nose down, stay above stall speed and find a place to land or use the parachute.
Power on (at idle), power off (prop windmilling - lots of drag), power off (propeller seized - no drag)?
Flaps up or flaps down?
Gear up or gear down?
Any combination of the above?
Item #39, in a "clean" configuration.
https://drive.google.com/file/d/1gbL...zi9ulGLFh/view