Octane additives?

Since I've had this motor it's ran on nothing but 100ll. It's got 596 heads with 202 valves and from everything I read there about 68 to 72 ccs? And I know I'm about five hundred thousand out of the hole with the flat top icon Pistons.

JPar, remeasure.........five hundred thousands ( .500 ) is a 1/2 inch!!!!!