To Change upper gears from bravo 1 to XR
 

Can someone help me to know how much do I have to shime to put in the XR gears on the normal bravo housing??

Thanks
Harry

Most of the old style housings were stamped
with the thickness of races required, on the face of the
rear of the case above and below where the the shift shaft
ran through.

The very last of the old styles and the slope backs
have a different proceedure, you shim the pinion to a specific height and set backlash with different thrust races.

Harry,
Typically the difference between the XR (or X) gears and the old style thin floored gears, is .040".. So If you case was stamped .091", then a .051" shim would be a starting point.
If you have an OM or newer drive then the shims are already around .061" and are added to or subtracted from that number, depending on lash. Using the new setup procedures from Merc is a must.

You must also change the input shaft yoke (or the entire shaft) to work with the XR pinion gear.

Hope that helps.
Dick

Thanks for your help Mr.Gadgets.

Harry