Have you confirmed that the spark is actually getting to the plugs? I've seen distributor rotors short out (or get misplaced) and even if the coil is firing, the spark doesn't make it to the plugs. Pull a wire off one of the spark plugs and use a spare plug or even a 1/4" bolt or something similar to test for spark to ground. I've also seen plugs get rusty and/or fouled during long term storage and leak firing voltage away without jumping the gap.
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!