What are the diferance between a XR-XZ drives

helical vs. straight cut(xr) gears up top....same lower end....im pretty sure

So which one is better/stronger???

Correct.

The XR is rated for higher HP. Ive heard the XR requires a bit more HP to turn it, and that the straight cut gears wear down faster under normal use too.....but these points seem moot to me. The drives are going to get abused no matter what. Have fun and get something non merc when your done.

Who makes a better drive then Merc.

IMCO EXTREME DRIVE OR TEAGUE PLATINUM DRIVE & BOTH CAN HANDLE 1000 HP AND BOLT UP TO A BRAVO 1 GIMBLE.
WHAT IS YOUR SET UP & IN WHAT BOAT?

I have 1999 -28 ft. Checkmate with a single 502 MPI . I upgraded to a Cyclone S.S. exhaust , large size flame assestor, MSD system,upgraded my cam and fuel system. as well .And installed a set of Dart 308 heads and reprogramded the ECM.

Your probably in the high 400 range HP? The teague and the IMCO are both better than the XR, but people break them too.....with a lot of HP its easy. I probably wouldnt be too worried with your set up. Just be easy in and out. If you want some extra insurance but want to skip the replacement stuff $$$, send your drive to Mr Gadgets end of this season and have him do the steel tower, cap, and tighten the tolerances. You will be fine. Your boat is a non step.....do an extension box, drive and tranny when you bump up the power big time.....or do the box anyway and see if you get some more MPH......chit, i dont know.

Kenneth,
For the power level you are running, I wouldnt consider the XR drive. The gears do wear out and they are expensive. You are better off sticking with the helical cut gears. If you want to beef up your B1, then an upgrade gear kit and steel tower and XR cap will make it the best helical cut Bravo you can get. If you get into the 6-700 hp range then think XR. I have a 99 28' Check also. Running a 565" motor and have not worn out my Bravo XR yet. But I do plan to build a new one soon.

Hope this helps.. If you want to discuss it give me a call and I can explain the differences and options of what is out there.

D*ck