Just a quick thought from my 8.8" to 9" swap...
The 9" had some odd ratios for certain.
My 8.8" 3.54 gears, the 9" had 3.50. Many cars have 4.10, the 9" have 4.11.
Though I can't think of what might resemble a 4.20 gear set. Interesting on the 4.22...never heard of that.
you have to remember that the ratio is the quotient between the number of ring gear teeth/number of pinion teeth. try to push the numbers around to see if that jives.
And for any hecklers...yes it is also the number of drive shaft rotations for each wheel rotation. The math works out the same.