Snapper Rear Engine Rider Re-power

I have a Snapper SR120 (I believe that's the name of it--I have the model # if needed) I want to replace the 8 hp Briggs and Stratton (that's seized up) with a 9 hp Briggs and Stratton engine off another Snapper Rear Engine Rider that I bought as a donor w/the 9 hp B&S engine that runs
I have a question about the wiring
I have a wiring diagram and I will look it over and compare it with my mower
But I know I will have questions and I was wondering if there were any suggestions out there
My...

Snapper Rear Engine Rider Re-power