How much horse power can a car have before illegal?

Answer 1

It varies from state to state, some states have no limit as long as it meets inspection criteria, some states limit it to 1000 or so horsepower, plus the power isn't what takes it off the road, its the modifications needed to accomodate that power, for a procharger engine of 2000 horsepower, for example, you'd need a custom rear and front transmission, new engine mounts, some custom fitting, redo the drivetrain, reinforced chassis and frame, roll cage probably, hood pins, tires, for a 7-8 second bracket car you'd need parachoutes too. I'd focus more on keeping it a functional reasonable vehicle than just making it a numbers game for horsepower.