Had a guy who builds performance boats locally tell me he swaps drives on twin motor boats every winter to make hrm last longer. Since they both spin different directions it makes the internal gears work in the opposite direction. I was told he does this because the driver that spins counter clockwise will always wear faster. Anyone else ever heard of this?or practice this? Yes I do know u must also switch the props

yes ive heard of this, if you think about it how often do you run your boat in reverse at full throttle,so swaping the drives would basicly be like running your drives in reverse which puts the load on the reverse gears and clutches but going forward which in sence would make your drives last longer..

Personally I can see good and bad. I would imagine there will be some gear experts here that will see this and hopefully have a good answer for you.

opinions vary on this issue i'm a marine mechanic and I say it wont hurt anything and its not a bad practice, but some people say keep port port and stbd stbd

One thing to keep in mind is how the drives were set up. I know when I set them up, I take into consideration their rotation. If resetting used upper gears, I will set up the better gears for that drives forward rotation. Also, I may set up the forward gear lash a bit tighter than reverse. Just my way, may not be the industry standard.

Mr. Gadgets, Dick Tryce, the guru of outdrives recommended that I do this.