Gripping the end of the club

This last weekend by accident when I was warming up I was taking some practice swings. As I was swinging back and forth the club slowly slipped down to where the pinky on my left hand was barely still holding on to the club. Even though it's not a classic grip it felt like I could really whip the club through when I held the club with the left pinky barely gripping the club. Seemed to get me about 10% more distance with my irons and higher than usual ball flight.

The only downside was that I would occasionally pull it left or push it right, which I do with my normal grip anyway.

Even though it seems to help I'm not sure why. Anyone know how holding off the left pinky grip (right-handed golfer) can give you a better whipping action through the ball?

Re: pinky finger off the end of the club: if you notice, every club has a raised place at the end of the grip(the end closest to you when you hold it), I always try to not grip here as I believe it was designed to hold the edge of the hands and not be gripped.
To get distance, try rotating the hands at impact or gripping with a loose grip to allow the wrists to unhinge naturally. The reason having your pinky off the club allows more whip is your grip is looser and the club is whipping naturally without the death grip.
Just my opinion, hope this helps.

It sounds like you need longer shafts. Check with your local pro to ensure your clubs are long enough for you.