Setting ignition timing by vacuum is about as accurate as:

Measure with a micrometer
Mark with chalk
Cut with an axe!

An Innova delay flash timing light is well worth the one time cost, especially if you melt the pistons on a couple of engines making a SWAG on timing! On at least a dozen dyno runs, I've discovered that one degree too much ignition timing robs as much power from an engine as 5 degrees retarded from the "sweet spot".

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!