Tire size

Hi guy's, I'm going to disc brakes and an 8 1/4 on my 72 Valiant. I plan on using 15 X 7 Cop car wheels for now. I like to know what's the best tire size to use. I've got a nice set of 235-60's I plan on using on the rear but they look to big for the front to me. Just like to know what you've had good luck with. Thanks.