I have a 35 with bravo drives and would like to put on XRs , who can help with this ? I think the problem I will have is all my stainless brackets for my steering will not work on the new drive. and dont know which ratio to run . the drives now have 1.36 spinning 28 p dravo 4 blades.

If your going from bravo to XR then everything should match up (unless you want extension boxes or some other add-on. Are you sure 1.36 and 28's, that would mean you got some big power. If your running something like 502 Mags then you likely have 1.65 drives.

Swapped over my last boat to Xrs easy swap only Diff is your gimbal bearing (which you should change anyway) The one that should be in it with a Xr has a red dot on it (there is a thickness diff in the bearings) other than that easy swap have your lower unit gone through as the one for a reg bravo is a little lighter duty. those are not the failure point in these drives anyway! ratio wise unless you want to buy a new props stay with what you have.. now for price Buy a Merc reman upper (little known fact ) same drive as new Diff part# and Diff warranty but all new drive no used parts.. they do this to stay in the game W/Ins company's plus you will like the price..
Have Fun! Bob
ps the XRs will have a nice whine to it because of the gear cut diff sounds like you have a SC in back! compared to the standard Bravo also don't forget to order decal kits for them!