741 rear pumpkin

[Purple73Cuda]

I have a 741 case with a 2.76 open rear. I would like to get a 3.23 or 3.55 Suregrip. Should I stick with a 741, so I can use the same driveshaft? Should I use a 742 or 489? What are the pros and cons of each different setup?

[HP2]

Changing to any of the other cases will not necessitate a new drive shaft as they are all dimensionally the same in that regard. The difference betweenthe all is the piniongear shaft diameter. Certainly a larger shaft will withstand more abuse. The 741 isn't necessarily a bad unit, it is just smaller than the other two. For a cruising application, it is just fine. If you are not doing 5000 rpm launches with slicks at the dragstrip, odds are it will hold up pretty decently. However, gear selection for the 741 is more limited than the other two. If you have to get all new internals for it, it is kind of a judgement call, IMO, on whether to keep the 741 or pick up a more widely available 489. You'll have to sit down and add up the figures, comapr them against your engine/driveline combo, and intended usage to see if it makes sense for you.

[Purple73Cuda]

I was under the impression that the 741 has the smaller yoke for the smaller u joints compared to the 742 and 489.

[burdar]

I don't think anyone make a NEW 3.23 gear set anymore.  You'll have to go "used" if that's the ratio you want.

[tactransman]

I was under the impression that the 741 has the smaller yoke for the smaller u joints compared to the 742 and 489.

No,you can get an adapter u joint any way.

[Chryco Psycho]

all carriers came with either the the smaller 7260 or the larger 7290 U joints depending on the application , for example you could get a car after 69 with a / 6 or a hemi but all had 489 carriers but you would not get a 7290 joint behind a slant 6
 the 742 is basically the best carrier to use as it has the second largest pinion size & no crush sleeve , the 489 has the largest pinion but uses the crush sleeve

[Purple73Cuda]

Does the 742 have a crush sleeve or shims? Are gear sets different between the three carriers?
Where would i get the adaptor u joint?

[tactransman]

742 = shims
489= crush sleeve

Gears are different
http://www.moparts.org/Tech/Archive/axle/1.html

conversion U joint

TRW part # 20226.
Mancini ........... 5-527X
Auto Zone ........... 2-0527
NAPA ............... NUJ240-0369
Neapco ............. 2-0527

[Purple73Cuda]

I had a brain fart. I meant to ask is the 741 crush sleeve or shims?

[Purple73Cuda]

742 = shims
489= crush sleeve

Gears are different
http://www.moparts.org/Tech/Archive/axle/1.html

conversion U joint

TRW part # 20226.
Mancini ........... 5-527X
Auto Zone ........... 2-0527
NAPA ............... NUJ240-0369
Neapco ............. 2-0527

Thanks. This is some good info!

[Chryco Psycho]

741 uses shims as well
there is an adapter to replace the crush sleeve & use shims in the 489 as well

[B5barracuda]

all carriers came with either the the smaller 7260 or the larger 7290 U joints depending on the application , for example you could get a car after 69 with a / 6 or a hemi but all had 489 carriers but you would not get a 7290 joint behind a slant 6
 the 742 is basically the best carrier to use as it has the second largest pinion size & no crush sleeve , the 489 has the largest pinion but uses the crush sleeve

 

also,of the larger two (742 489) castings,the 742 uses the clutch style suregrip the 489 uses the cone style.
the clutch type is much better than the cone style (in my opinion)
if you gonna beat on it ,go with the 742.....

[shadango]

Purple73Cuda --- AWESOME QUESTION!

This is AWESOME info ....I have the same situation...a 741 with 2.76s, looking for 3.54s, preferably sure grip! 

[Purple73Cuda]

Shadango thanks!
I looked at my parts car ('70 Satellite) hoping to find an 8 3/4 rear. I figured maybe it would have 3.23 in it. It turns out it has an 8 1/4 rear. As I am walking back to the front of the yard I see my '67 NYer. I think, I wonder what is in that car. I look under ands it is an 8 3/4. I pop the hood and look at the fender tag and I see AX18. Sweet! It has a suregrip. I run into the house and look at my decoder book. It decodes as a 2.76 suregrip. I want more gear but that pumopkin will give me suregrip til I find what I want. Right now my plan is to swap pumpkins. I think I want a 3.23 or 3.55 Sure grip for the 'Cuda. Surprisingly (sic) the 'Cuda goes pretty good with the 2.76s.

[Changin Gears]

The best bet for finding steeper gears (3.55, 3.91) in a bone yard is the trucks and vans.