bought a job lot of stuff today some of which was diffs

got a standard 3.62
and a box of cogs along with an empty case
one crownwheel has 3.92 on it and another one i cant read
the casing has 14 teeth on the pinion

basically i need to work out which crown wheel is for this casing and which one is spare??

 

A=3.36(crown wheel 44 teeth, pinion 13 teeth, 7.5" diff casing) B=3.77 D=3.92(crown wheel 51 teeth,pinion 13 teeth, 7" diff casing )
F=3.842 J=4.056 K=3.31
M=3.14(crown wheel 47 teeth, pinion 15 teeth, 7"/7.5" diff casing) N=4.29 P=3.58
U=3.62(7" diff casing) V=3.33(crown wheel 47 teeth, pinion 13 teeth, 7" diff casing) Z=3.59
2=4.27 3=3.62 / 3.64? 4=3.82
5=3.26 6=3.12 8=3.56
9=3.91(7.5" diff casing)

 

the mystery crownwheel has 51 teeth and the pinion has 14
the spare crownwheel has 3.9 stamped

 

ok the fella rung me today and told me id left behind a diff casing

top bloke

all i need to do now is work out which crownwheel is for which diff?

one is fatter than the other and one casing is a 7.5 and the other is a 7