Bravo 1 vs Bravo 1 X
 

What is the difference between a 2001 bravo 1 and 2003 bravo 1 X?

Details here
http://www.go-fast.com/mercruiser_bravo_sterndrives.htm

Mainly the steel tower in the upper case. A steel tower can be added to your B1 if desired. The upper case for the B1 X is an XR upper, it has the larger retainer for the pinion and consequently is thinner in that area. The 2001 should be an OM drive and have the X gears in it, just like the B1 X. Input shaft is the XR style (larger ujoints), so the X gears are actually the same as the old XZ drive. Only difference between the X and XZ gears is the ID of the pinion gear (it is larger to fit the larger input shaft) As the chart that Griff pointed out, shows.

Dick

So what would you do? I have both drives, I just bought the Kachina with the X drive. When I changed the oil I found 2 small metal pieces on the drain plug magnet. The motor has 425 hp. I have a bravo 1 on another boat that has low hours. Can I switch them and not harm the outdrives? My other boat only has 300 hp.

The X drive would be the stronger of the two. But at 425hp and driven with respect, the B1 should live a long life behind that motor. That being said, you could look into the X drive to see where the metal came from, more than likely the lower gears are starting to pit, get it fixed and swap back, keep the B1 for a spare, if you wanted.
I would not be afraid to run the B1, driven with respect ( no hole shots, easy on plain, no WOT till you get the hull aired out, and timed throttle back on exit and reentry of the prop).
Hope that helps.
Dick

Thank you.