Old gearhead, but new to MOPARs
Did you figure anything out with regards to the rear end ? If you can locate the casting numbers on the rear. If it is a "741" ( the small pinion 1 3/8" ) 8 3/4 the casting will have a large X cast in the left side.
If the rear is the "742" this is the large pinion rear ( 1 3/4" ) it may have a large 2 cast on the left side.
If the rear is the "489" this is the tapered pinion ( 1 7/8" ) it will have a large 9 stamped in it. Through 1965 the ratio was stamped in the id boss of the rear end followed by an S for sure grip. After 65 the ratio was stamped in a tag that was located under the carrier mounting nuts. Sometimes there was a Sure Grip lube tag applied or as crazy as this is the filler nut/plug was painted orange.
Let us know what ya find man.
If the rear is the "742" this is the large pinion rear ( 1 3/4" ) it may have a large 2 cast on the left side.
If the rear is the "489" this is the tapered pinion ( 1 7/8" ) it will have a large 9 stamped in it. Through 1965 the ratio was stamped in the id boss of the rear end followed by an S for sure grip. After 65 the ratio was stamped in a tag that was located under the carrier mounting nuts. Sometimes there was a Sure Grip lube tag applied or as crazy as this is the filler nut/plug was painted orange.
Let us know what ya find man.

Yep -it's got the big "X". Obviously the pinions aren't interchangable between the above, but what about the posi?
Also, when I pulled a wheel, it has an axle flange just like a 9" Ford would have.
Last edited by GrabberOrange69; Nov 8, 2009 at 03:57 PM.
The two sure grips can be interchanged between the carriers if the matching differential axle bearings are retained. The outside cup diameter is the same between 741/742 and with the 489 the inner cone differs. Prior to 64 there are thrust block differences which F&ck things up.
Clear as mud ?
Ask away man, I got loads of paper on this stuff.
I also have axle data too Bryan. Let me know man.
Clear as mud ?
Ask away man, I got loads of paper on this stuff.
I also have axle data too Bryan. Let me know man.
Last edited by Polaradude; Nov 9, 2009 at 12:23 PM.
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