For drag racing, can I go with a smaller rim on the back with a bigger tire and keep my 19 on the front?

2008 Ford Mustang

Right now i'm sitting at 245/45r19 fronts and rears 275/40r19

The reason for asking is because i can't find a drag radial or Slick that fits my rim?

Hi so what happens when you get stopped next time and they check your boots and find odd series tires back and front.

Nobody knows?