What is the difference between the two out drives?

What a sillly question! One ends with a Z, and the other ends with an R.




One has straight-cut gears and the other doesn't.

same lower.....different upper. As Phantom said, the XZ has spiral cut gears that are much weaker than the straight cut gears of the XR.
Eddie

XZ discontinued, but faster. As stated they are weaker then the XR. But it all depends on the batch of gears you get. I have heard of issues with XR gears as of late.

How do these gears differ from the Bravo One? I had heard that Bravo One is the fastest, but weakest?

Is there a difference in the size of the ujoints. How about a break down on the bravo line, x xz xr , ???????

Post #6 answered that question for ya !!! ( partly )

See if this helps

http://go-fast.com/mercruiser_bravo_sterndrives.htm

Thanks for the info.