Very intriguing, even though I have not followed NASCAR for 3 seasons...
Going from a platform that focuses on control (re: AWD and relatively lightweight) to a platform that is very easy to lose control of (re: RWD and relatively heavy) is not easy. In other words, he is going from a car that can literally be thrown around to a car that tests the driver's ability to restrain himself (re: not overdo it).
Also, in NASCAR the driver must be very aware of how the air is passing over his car. Other drivers will maneuver in a way to make the back of the car in front lose downforce on the rear, which will cause the driver in front to spin. Don't even get me started on tires...
Let's see how quickly he learns with over 40 cars surrounding him.
I hope he does well!
70 to engine rebuild faster than you can say "poofff!"