Due to the oddball shape of the combustion chamber on a stovebolt engine, the rope trick probably won't work well to do a head-on valve spring removal. The exhaust valve will be difficult to hold against the seat that way. Air pressure works well- - - -but- - - -put the transmission in gear and set the parking brake and/or chock the wheels to keep the engine from turning before turning the air on. Two pairs of vise grips on the flywheel at the bottom of the bellhousing also works, especially if you happen to be working with an engine with an automatic transmission.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!