We are in the middle of a drive build and need to know what will handle a 9k boat with twin 575sci's. We are torn with both but long term is what we are looking for... ideas???

Thanks

xr is stronger. XZ was the first answer with hardened gears but not straight cut gears like the xr.

As long as the XZ's can handle the HP, which they should be able to just fine, they will last longer. XR gears tend to wear out faster, but are needed for bigger HP.

With that application definitely the XR.

Well, have 8 hrs on a new set of xr's with pinion gear failure... not having the warm fuzzy feeling... lol

BTW, they were cryo'd too.... one drive gear was pitted, the primary's were fine.... both drives had same problems... merc is covering them but not sure if we want to tear down every 8 hrs...

I kind of wonder about the cryo. I've seen stock bravos last that long with more hp. Pitting is more a manufacturing issue than "usage" issue.

right... thats what my husband thought... he's a mechanical engineer and is actually disecting one of them to have a metalurgy test done.. he has a few guys he works with that can do this... he thinks that they had a bad heat treat run...

How about using the new Imco SCX set up? It will work with the Bravo Transom assemblies, you just need to swap out the helmet. They are rated for quite a bit more than what your 575's should throw at them.. If they may interest you feel free to contact me.. Jamie / Lakeside Restorations

Sounds vaguely familliar to what I had happen a couple
of years ago , although one of my driven gears
started to chunk out too. ( they were a brand new set also)

If and when mine crap out again, I think I'm
going to try the helical type ( X/XZ)

Any experience with the Billet marine XR uppers with there Imco billet lowers ? This is our solution for our build this winter and wondering about others experience with them.