Stock Excel...not sure what that means. Excel rims are aftermarket and are made for a lot of different applications. The really affordable ones are made to fit dirt bikes....and the spoke angle is most likely not correct.
The Savage rear hub is a brake drum, and if you get an Excel rim that has been drilled for a rear hub that uses a disc brake, the diameter of the hub will be smaller than the Savage drum - the holes in the rim for the spoke nipples will most likely be punched/drilled at the wrong angle for the Savage. You either need to take a drill and change the angle of the holes (not recommended).....or order an Excel rim from Buchanan's that has the holes drilled at the correct angle for the Savage.
If you can find a rim for an older Suzuki GT380/GT550, T500....somethings with a rear brake drum...they may have a rim with the correct spoke angle. Most likely it will be a chrome plated steel rim.
http://www.buchananspokes.com/categories/excel.asp