There is a pinch-type clamp at the bottom of the distributor housing secured with a 1/4-20 machine screw (AKA "Stove Bolt") that can be loosened, which will allow you to turn the housing in a complete circle. Start out by centering the small slot where the distributor bolts to the block, lock it down, and use the pinch clamp to adjust the timing.
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!