Sam, you're right...I think I was having a "Sheldon Cooper" moment there.
A *truly* pure stock L72 won't measure an honest 11-1 compression, it will probably be closer to 10-1 (see Rob Clary's comments on the 2nd page of
this thread). As such, you should be able to run pump premium (possibly with a splash of race gas) as long as the temp and timing are kept in check, and the carb is set up correctly.
Sorry for the data dump.