Just don’t do what I did to my go kart years ago (I drove it one time after, never again)
I took the little 12 or 14hp motor off and transplanted a 4 Cylinder from a Suzuki GS750 Motorcycle onto it. That’s roughly a 110-120hp in-line 4 from a Muscle Bike that had a top speed of 150+ on a bike that weighed 700 pounds.
I thought it’d be a good upgrade for the go kart...