8 3/4 casing

[Ken56]

Can I put a 742 or 489 carrier in the same casing as the 741 I currently have? If yes can I use the same axles?
Thanks, Ken

 

[StreetWedge65]

No. All three will fit any 8¾" housing. Carriers are different internally.

 

[91r/t]

Can I put a 742 or 489 carrier in the same casing as the 741 I currently have? If yes can I use the same axles?
Thanks, Ken

Confusing way to word it. No biggie. The 8.75 housing is the same for all setups. (minus axle tube length, shackle location.)If you have a complete carrier (741, 742, or 489), they will all bolt into the housing and all should be 30 spline axles stock. Now if you are talking the parts from the carriers themselves, they will not interchange with each other. (pinions, bearings, etc.) The thing to watch is the 489 uses the bigger u joint, so you will need a conversion joint if you plan to use the 741 or 742 style driveshaft. Also, make sure your carrier has the correct thrust bushing in it if you plan to use stock style tapered bearings so you can set the bearing preload correctly.

 

[Dipstick]

Regarding axle shaft interchangeability, be aware that the pre-'64 8 3/4" used different length axles for Sure-Grip and open differentials.

 

[Ken56]

Thanks to all, Information was very helpful. I have a 66 Belvedere with a 741 suregrip carrier and wanted to put a 742 carrier in the same housing for more strength to handle the 500+ HP engine.

 

[beanhead]

Thanks to all, Information was very helpful. I have a 66 Belvedere with a 741 suregrip carrier and wanted to put a 742 carrier in the same housing for more strength to handle the 500+ HP engine.

Yes you can. The yoke fits the bigger u-joints is all. Which, hopefully you're swapping to bigger u-joints anyway with that much power..

 

[33 IMP]

You might want to check with Dr Diff first. I won't put words in his mouth, but I believe he thinks the 741 case is very underrated. It's primary drawback is poor gear ratio selection.
If you look at all three pinion designs, the neck-down for the yoke is the SAME on all three, essentially making them all the same strength.
If you have a stick, a Dana might be advised, for an auto, especially without slicks, a 741 might be fine.

 

[Ken56]

You might want to check with Dr Diff first. I won't put words in his mouth, but I believe he thinks the 741 case is very underrated. It's primary drawback is poor gear ratio selection.
If you look at all three pinion designs, the neck-down for the yoke is the SAME on all three, essentially making them all the same strength.
If you have a stick, a Dana might be advised, for an auto, especially without slicks, a 741 might be fine.

 

[Ken56]

Good info, I'm running street tires right now with a 4 speed. I don't race the car but I like to go to the track for test & tune. It don't hook up until I hit second gear but it's a lot of fun to drive. I haven't broken the 741 yet but I'd feel more comfortable with the 742.

 

[threewood]

You might want to check with Dr Diff first. I won't put words in his mouth, but I believe he thinks the 741 case is very underrated. It's primary drawback is poor gear ratio selection.
If you look at all three pinion designs, the neck-down for the yoke is the SAME on all three, essentially making them all the same strength.
If you have a stick, a Dana might be advised, for an auto, especially without slicks, a 741 might be fine.

The 741 was used behind the max wedge cars in the early 60's. Gear deflection and chewed up ring gears will happen before the pinion gives out.

 

[91r/t]

Yes you can. The yoke fits the bigger u-joints is all. Which, hopefully you're swapping to bigger u-joints anyway with that much power..

741 and 742 use the same U joint. 489 is the one with the 7290 U joint vs. the 7260 for the other 2.

 

[91r/t]

I was running a 741 carrier in my Charger with 550 HP. You really have nothing to worry about if your street driving with street tires. You will break traction before anything is broke. Now if your running slicks and launching at the strip, then you may want to look into bigger carrier/Ujoint combos.

 

[Dipstick]

741 and 742 use the same U joint. 489 is the one with the 7290 U joint vs. the 7260 for the other 2.

The 7290 was introduced in '67, well before the 489, so it was also used on the 742.

 

[Fran Blacker]

I was running a 741 carrier in my Charger with 550 HP. You really have nothing to worry about if your street driving with street tires. You will break traction before anything is broke. Now if your running slicks and launching at the strip, then you may want to look into bigger carrier/Ujoint combos.

742's also used 1330 u-joints for Bb and Hemis.

 

[Dipstick]

The 741 was used behind the max wedge cars in the early 60's. Gear deflection and chewed up ring gears will happen before the pinion gives out.

Actually the Max Wedge never used the 741, they used either the 742 or the earlier 985 (both have the 1 3/4" pinion).

 

[91r/t]

742's also used 1330 u-joints for Bb and Hemis.

7260 and a 1330 different? Hmmmm learn a new one every day. Was always told small u joint 741,742 and big 489. Is that the u joint with the small caps but is very wide???

 

[Fran Blacker]

It is 3 5/8" same as 7290 just the diameter of the cups are different. Had a 7290 driveshaft and a 1330 yoke back in the 80's. Bought a 1330 u-joint and put the cups on the 7290. Don't know if they made combination u-joints then. 1330 u-joints were used in 66 and maybe 67.
If you use a 742 housing the pinion seal I'm told is unique to that housing. Removed the original seal from mine recently its a C/R 18912.

 

[91r/t]

It is 3 5/8" same as 7290 just the diameter of the cups are different. Had a 7290 driveshaft and a 1330 yoke back in the 80's. Bought a 1330 u-joint and put the cups on the 7290. Don't know if they made combination u-joints then. 1330 u-joints were used in 66 and maybe 67.
If you use a 742 housing the pinion seal I'm told is unique to that housing. Removed the original seal from mine recently its a C/R 18912.

Ahhhh thats probably why. I deal with 68-71 stuff so there was always the 2 1/8" small joint and the 2 5/8" large joint. Very rarely would I run into that. Good info though for sure!!! Thanks!

 

[67Charger]

Ring gear carriers (the differential) are interchangeable if you use the correct bearings and races for the carrier. All carrier bearing race OD's are the same, but bearing ID's were different.

Ring/pinions can only be used in the type of housing they were designed for: 741/742/489

All 3 common u-joints are pretty close in size:

• 7260/7290 u-joints are internal C-clip and have small ~2 1/8" and ~2 5/8" measurements respectively FROM CLIP TO CLIP, but are over 3" wide overall
• 1330's are external C-clip measured OUTSIDE TO OUTSIDE. They are installed without clips at the diff since the yoke has tabs for the ends.
• IIRC, 1350 is a 1330 with bigger 1 1/8" caps instead of the 1330's 1 1/16"
• Conversion joints exist for every combination of those 3, but some are getting harder to find. I just bought 1350/1330 and 1330/7260 last week.