You may get by replacing a Briggs and Stratton engine with a Honda on your lawn mower without getting into trouble with the EPA or insurance company regulations, besides its an offroad vehicle. But the EPA is now getting involved with offroad stuff as well.
Each and every on road vehicle has to be certified by the EPA to meet their emission requirements, granted another engine may also meet those requirements, but not in the vehicle it was intended for. Not dealing with logic, but with the EPA.
If your insurance company or the other guys who is a fault, may find zero coverage if your vehicle was modified in anyway, even if this doesn't have anything to do with an accident. They hire not so honest "experts" to check over your vehicle, and even not so honest doctors to say in court, you weren't hurt so bad.
Most people are not even aware of this until it happens. If you do modify your vehicle in anyway, read your fine print, have to report these mods to your insurance company. Liability has really crossed the boundaries in this land of the free and the home of the brave.
No such thing as a bolt on supercharger or turbo, has be a ground up design. Those that have tried blew up their engines.
Ironically today with all these "green" people there are more over 500 HP vehicles available ever before in our history, it makes the 60's and early 70's look like kids stuff. They also have to meet all governmental regulations, but it only takes $$$$$ to buy one.
55 still means 55, never in our history did we have more cops on the road.
