When you run the same stuff as everyone else, you will run just like everyone else, unless driver and chassis are that much different..
But, then again, I always was a bit different.
If you are not limited to stock engines, I would stick with the Kohler and begin to modify it.
Otherwise, if you insist on the Briggs, Billet wheel. Port the head, mill .100" off it. Good carb. Isky #95 cam (if you manage to get in contact with him, or can find one).
If you want to come off the corner, go Tecumseh....but, not much availability and have to be creative.