Frank,
That depends on the speed and direction the plane is going when you bail out. If the aircraft is traveling horizontally at over 100 MPH then 600 to 700 feet would work. A friend of mine bailed out 3 months ago at 800 feet after a control stick failure with his plane going straight down and he hit the ground before his chute fully opened and didn't survive. The emergency chutes we wear don't have sliders to slow the opening and reduce the opening shock so they open hard and fast. Even with a successful deployment however there is a lot of risk to a untrained non-skydiver bailing out over unknown terrain so jumping would be a last resort.
Freddy,
The 540 Lycoming is a flat-opposed 6 cylinder, air cooled, engine. Mine was specially built with fuel injection, high compression pistons, and inverted fuel and oil systems so it will run upside down, straight up, straight down, or upright, and it has 330 horsepower. RPM is limited to 2750 to keep the prop tips from going supersonic which would kill their efficiency.
Chip