Diff ratio question

[Kenneth T.]

I have a diff for a long while.and today I brushed off the bottom
and it is stamped 1 FA 9 67

I suspect this one is a 67.
It is the ratio that I am confused about, ???

[Michael G.]

Re: Diff ratio question

Ken, The simplest way would be to count how many rotations of the drive shaft pinion it takes to rotate the axle flange one full turn. (3.08 turns,4.11 turns, etc.) Mike

[John H.]

Re: Diff ratio question

I have a diff for a long while.and today I brushed off the bottom
and it is stamped 1 FA 9 67

I suspect this one is a 67.
It is the ratio that I am confused about, ???

"FA" was used from '65-'69 for a 3.70 Posi big-block (bolted yoke caps) diff; with a September '67 date, it would be from a '68.

[Kenneth T.]

Re: Diff ratio question

"FA" was used from '65-'69 for a 3.70 Posi big-block (bolted yoke caps) diff; with a September '67 date, it would be from a '68.

Thanks John,

It has bolted yoke caps, so BB early 68.
Ken