History of Fire up road to hand held Starters

This will tell a little about starters and rollers.

http://joe-smith-drag-racer-true-bench-racin.blogspot.com/2007/07/my-double-engine-dragster-starter-motor.html

How many motors

Yes to all that! As I recall they even tried two Buicks and also two Chevy’s. The one I drove was on gas and it turned in the nines with that one Chevy motor, I just remember it was a fun time that night, I loved night racing. A good example of "in the direction you are talking about" on a flow bench, try a straight tube verses a tube with the bell shape on the end. The same size motor will do different things with the right changes