hahaha, 673 rpm. What a guy. No, the balls didn't have internal weights
I asked question based on the numbers. This has nothing to do with internal weights or how people bowl differently then compared to now. It also pertains to the type of motion that the USBC describes as the roll phase.
The circumference of a bowling ball is 26.7 inches. Since it was likely a full roller, I can assume that the entire circumference of the ball has to touch the lane in one rotation.
A bowling lane is 720 inches from the foul line to the head pin.
(720 in)/(26.7 in/rotation) = 26.96 rotations in one trip down lane.
A bowling ball thrown at 17 mph would reach the head pin in 2.4 seconds. If we assume it never slides and only rolls (the roll phase), it would have to complete all 26.96 rotations in 2.4 seconds.
(26.96 rotations)/(2.4 seconds) = 11.2 rotations/second
(11.2 rotations/second)*(60 seconds/min)=674 rotations/minute
To never slide and only roll, a ball released at 17 mph would have to have 674 rpm the instant it touched the lane. That means 674 rpm off of the hand.