Bergers at LOTO recommends doing this as well.

The running in reverse. If you mean reverse as reverse that is not ever a problem, you are putting no load as to speak.
But if you are referring to Bravo's reversing the drives from one side as Port to Starboard. You would more than likely not be doing this after several hours are on the drives. That would shorten the life of the gears. If doing it in very earily stage, such as to test the boat for better operation. Than it more than likely would not have to much effect on the gears.
Because you haven't put enough load on the gears as of yet. But you wouldn't want to do this after a few hours, you would lessen the life of the gears greatly. I hope this helps.

This brings up some good points. Another thing to think about is switching prop rotations from turning out to in or vise versa. I guess the correct way to do that would be to also switch the drives from side to side once you decide which way to run?

Thanks everyone ! I guess it's better not to swap if John is correct.

Yeah, I guess I'm confused as to yes or no, different opinions.... Seems like a good idea......
Dean

First of all what are we talking about a stock application or a 700hp and up? I have been swapping drives for years and have never had one come apart.
When you buy a reman unit how do you know what side of the boat the used shafts were on before? Be careful how you answer that because you may start a up roar with a lot of re-builders. I do agree that if you are swapping drives on a boat that has twisted splines already you will soon be paddling back to the dock. There are a lot of variables that go with this conversion and each owner and their boating habits and power have a big roll in this.
We have all broken Merc vert shafts, they are like a chicken wish bone some times they stretch and sometimes they snap.

I like fried chicken....

I agree with Waconda and about everyone else on this thread. Way too many variables. In a perfect situation, I personallt think swapping drive is acceptable.

John, my spare does have new shafts doesn't it????

I just used JB weld and put the old one back together, it was original merc so I thought we needed to keep it. How is it holding up?

Running good im my garage so far.....

Other ones are livng fine with that blue oil of yours in it.... Got any guages laying around there you would swap for a full BT cover?

Well I have swapped upper helical gears and lower gears. So long as the net forged ones havent started to pit, it seems to last. But when they are pited, or just started, then the life expectancy may not be equal to the time running in the opposite direction. Now the helical uppers, if not over taxed, seem to like being flipped.
The XR uppers, it seems to be the pinion gear that starts to pit, so fipping them doesnt help. Of course if you are unlucky and have a driven gear with a weak tooth, that might break before you get a chance to flip them, or it may happen soon after you flip them. By fliping, I mean either change the position of the gears, or swaping props or drives, etc.

In the upper, the pinion drives both gears. The cone will engage either the upper or lower for forward or reverse, depending on what rotation of prop you have on the drive. RH prop = bottom upper gear, and so on.
In the lower the pinion gear will put pressure on the opposite side of the gears when rotation is switched.

Hope this helps explain to those that are not familar with how the bravo works before it breaks.

Dick