the problem is when the insurance assessor inspects ur car, then when he/she reports it to the insurance company, then they gonna try refuse ur claim, coz ur new engine is not registered to the car, which makes it illegal. the problem with u is that insurance will ask y were u driving d car if ur not listed as a driver, also they will ask ur dad y did he let u drive it 1st place. so either way ur fukd bcoz they not going to pay u out.