You'll need to advance the initial timing about 10 degrees above stock, BUT, the centrifugal advance needs to be reduced by the same amount. With the vacuum advance disconnected and the line plugged, shoot for 37 degrees total advance at 2500-3000 RPM. It's usually necessary to have somebody recurve the centrifugal advance in the distributor to get those nunbers. Simply increasing the initial advance will result in too much total spark advance, and overheating and/or piston damage.
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!