They evolved over time. Small changes from year to year, but the basic architecture stayed the same. Lots of time the changes are visible, .ie the change from magneto ignition to electronic, or the change from Tillotson carbs to MerCarbs. Others are more subtle, as in the change from 11-spline propshaft to 13-spline, or going up a size in the mounting studs on the lower unit.
Do you know if the mid sections ever changed? I found a short shaft mid section on Ebay and I'll pick it up if there is something available. The shorter the shaft the better for my project.
If you checked you conversion topic, you'd see that Chinewalker already gave you advice about your mid section conversion plan. Thats one of the reasons we strongly suggest having 1 topic per project, motor or boat.
Prevents duplication of effort and you get the info and help all in one place to reduce confusion.
You posted there too but didnt acknowledge Chines comments about the mid sections, so I dont know if you read it or not.
