Then how do people manage to insure modified vehicles? My Chevy truck makes 3 times the power it did stock (went from a 2.8 V6 to a well built 383 V8) but it is insured as stock, using the VIN. I have recently become interested in rat rods. Most of those are titled and insured by the VIN that is on the frame, as whatever the frame came from. In AZ the frame needs to be a '66 or older to get you out of having to deal with emissions. Fortunately there is no longer any emissions crap to deal with for motorcycles. We finally joined the other civilized 49 states.