Mr. Billion (1977)

Anthony Falcon is a billionaire. After he dies, he leaves his entire estate to his Italian nephew, Guido Falcone, a mechanic who wishes to be a cowboy. To get his inheritance, he has to go to California and within a specified time or the estate will fall under the control of the executor, John Cutler, who wishes that to happen. And it might just happen, cause Guido doesn't like to fly, so by the time he gets to America, he will just have enough time to get there. But running into some undesirable individuals, he loses all of his money and has to find a way to get there. Cutler has also sent Rosie Jones to try to get Guido to sign a paper, wherein he relinquishes all claims to the estate but she instead falls for him.