Help w/ 7 1/4 to 8 3/4 change over

Wheels I had a set of 14x5 s.b.p steels on this until I changed the front brakes to 73 up disc
So now I have Rally wheels 15x7 l.b.p on the front and 15x7 s.b.p. on the rear 7 1/4 axle.
This will change to a 15x8 l.b.p. when I install the 8 1/4 .
Tires I'm running now are 205/65Rx15 . When I change the rear end I hope to run 245/60R15 on the rear. Dart Left.jpg Dart Left.jpg Dart lr.jpg