How in HECK to you figure HP on a B&S engine?

My craftsman is a torque rating (18.5?) but I think I'd rather have a torque beast to swing the big blade instead of a high rpm screamer as it doesn't get above 3000? I have a wimpy snowflake electric mower picked up for free amd that thing is a pos. 24v out of 2 UPS batteries in series spins a light blade that can barely cut the tops of the dandelions and bag them . I was going to use the motor for a bike electrification but have not attacked it yet as its really a wimp.