My "leakdown tester" is nothing but a pressure regulator installed in an air line. With the hose plugged off and no air flowing, adjust the pressure to 100 PSI, and then connect the coupler to a quick-connect fitting brazed into an old spark plug shell. If the pressure drops to 89 PSI, for instance, that's 11% leakage. Listening at the intake, exhaust, and oil filler for airflow will tell where the pressure is escaping. Bubbles in the radiator indicate a leaky head gasket or a cracked head.
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!