swapping a lawn mower engine

I am new to the forum.
I have a Briggs and Stratton Vanguard 15.5 hp model 28Q777 in a Toro Lawn Mower that doesn't run. I'm wondering if I can swap out with a Kohler Commander 15 HP Model CV15S Spec# 41515 (a friend has this and will let me have it).
Do shaft length and diameter match up as well as mounting holes and electric for starter.

Any help is appreciated.

Thanks