need axle ratio and tire size chart

she was looking for Starting Line Ratio
2.45(trans) X 4.56 gear

We took the "A" body rear out (245/60 -14) 7" wide wheel, 3.91 gear
Put a "B" body rear in (4.56 spool)
So, that we can run 15"x 8" wheels
ended up with a 255/60 - 15

The 275/60-15 put us at the same ratio as the "A" body set up, just more tire, on the ground
It looked good on there, filling up the wheel well