I am replacing my 14hp Briggs and Stratton Vanguard engine on a Rover Rancher ride on mower?

I have a Rover Rancher ride on mower with a Briggs and Stratton Vanguard OHV 14hp engine on it which needs to be replaced, but I would like to know what options I have in the way of engines and CC size to replace the 14hp. If anyone could help me please do as I urgently need to get these lawns around here done before xmas.