Suregrip and open differential gears

[RD]

the pinion size is the difference between the 741,42 and 489.  How often do you hear the pinion breaking?  It is most likely the ring gear or the carrier main caps that break, but not the pinion.

[SpudRacer]

The 741 has a pinion size of 1-3/8" and should be avoided for high horsepower applications.
The 742 has a 1-3/4" pinion and should be OK for most applications.
The 489 has a 1-7/8" pinion size and is the mother of pinions!!

Hope that helps...

[RD]

The 741 has a pinion size of 1-3/8" and should be avoided for high horsepower applications.
The 742 has a 1-3/4" pinion and should be OK for most applications.
The 489 has a 1-7/8" pinion size and is the mother of pinions!!

Hope that helps...

i have ran a 71 dodge charger (heavy car) that was a nothing but a drag car on a 741 case with 3.91's for 4 seasons and no breakage.  again, its not the pinion that is most likely to break, look above.

[SpudRacer]

I drive (with the gas prices, push) a 69' Charger, and haven't yet looked at the casing number.  Where is the number stamped on the 3rd member?  I should have clarified that the data I provided was "gleened" from another web site and doesn't reflect my own opinions.  I have never heard of a pinion break either.  I've only broken U-joints, never even an axle.  I suspect a U-joint or axle would let loose long before a pinion would shatter unless it had a manufacture defect.

I'm planning to eventually slide a Indy Engines 528 Street Legend under the hood and will leave the rear end stock UNLESS something breaks at which point I'll upgrade.   This is way down the road though.

[Nacho-RT74]

as website says, difference is also on inner cone bearing cup

[John_Kunkel]

the pinion size is the difference between the 741,42 and 489.   How often do you hear the pinion breaking?   It is most likely the ring gear or the carrier main caps that break, but not the pinion.

It isn't about the shaft snapping off, all of the pinions neck down to the same size where the yoke attaches.

The larger pinion shaft resists gear deflection which is the ultimate cause of gear tooth failure.