Back in their day these were two very fast combinations. One noticeable difference is the better props . Back in the early 70’s here in Ontario Canada you were lucky if you could find and purchase even a two blade stainless mercury prop. You got a lot of shaking and vibration getting on plane with the two blade props, but they ran well once they were on plane.
MX15 Mercury 1500XS
https://www.youtube.com/watch?v=gJvcWEom8oUMX13 80 hp Mercury Short Shaft
https://www.youtube.com/watch?v=ZVfLacl ... 4JAYcqIYzvhttps://www.youtube.com/watch?v=EWNWwJj1lG0&t=153s
