Paul,
Over the years I've hand cranked a lot of engines in all kinds of things. None of them were Chevy 6's, but there were some farm tractors with bigger 6's. Also hand propped a few airplanes.
They aren't really trying to kill you. As long as you pay attention to what you are doing, it works out just fine.
When I was a kid I couldn't crank over the old Fordson steel wheeled tractor. Think I was 13 before I could turn it over with both hands. Before that I would bring a milk crate, get the crank to the right position, switch on, and jump off the crate onto the handle. Got it started more often than not and never got whacked.
Being Young, dumb and lucky helps.
