I'm with chiphead on this one. Why fight it? Build the engine for the fuel available and avoid the hassles. If the right cam is selected during rebuild, the effective compression ratio at RPM will be increased without damage to the engine. The cam manufacturers can help pick the right one for your application.
Of course, if you have a good engine already running like the 427 here, this isn't much help. Retarding the timing a couple of degrees and richening the mixture are about the best you can do (in addition to octane boosters), unless you want to spend a weekend changing to thicker head gaskets-which won't drop the ratio much.
One other thing: Get a vacuum advance can that pulls off timing sooner. GM makes one for the HEI that will start dropping advance at about 15 inches of vacuum.
Good luck,
Banjo
