3.77 diff

Well it’s getting a bit milder outside so I decided to venture out and open my spare diff with a view to putting a quaife ATB inside and then fitting it later this year.
Upon opening it,checked the teeth and yes 34 and 9 giving the 3.77 ratio,BUT,written on the crownwheel and end of the pinion was 3.39R.
Can anyone throw any light on this?
Perplexed
John :wink:

Maybe it was destined to be mated with a 10 tooth pinion, which would give it a 3.40 ratio? Close? Don’t know really, just a guess.

Greg Z
'72 Sprint