Spark plug indexing is one of those things that, by itself is almost insignificant. But adding up all of those little things can result in somewhat of a power increase . . . .
As long as your piston dome to plug electrode clearance is not an issue, then the plug gap should be pointed towards the intake valve.
As long as your piston dome to plug electrode clearance is not an issue, then the plug gap should be pointed towards the intake valve.