Combination U-Joint 741 to 742 Swap

[Belvedere13]

Getting close to having the 742 case completed with Sure-grip and 3.73 gears for the Wagon. Currently, there is a 741 case installed and the replacement 742 has the larger 10 spline yoke. My research so far suggests Moog 319 or Moog 347. What is the correct combination U-Joint to go from the OEM driveshaft yoke to the 742 Case? TIA

 

[Bill Monk]

347

 

[Fran Blacker]

Does your yoke have small tabs (1330) to center u-joint or is it machined for inside snap ring? Pic is of tabs, little hard to see. One with tape measure,

picture is of a 7290 yoke machined inside.

 

[65wgn440]

Mancini sells them.

 

[HEMI-ITIS]

Do the larger joints now front and rear.You can have your shaft modified or buy new CM or aluminum to save some weight.

 

[Belvedere13]

Thanks guys...I believe it has the tabs to center the U-Joint. It's in the process of being re-assembled so I will confirm before ordering a U-Joint. An aluminum driveshaft might be something in the future but for now I have other "priorities" for the Wagon and I'm trying to stay under the Wife's radar...Moog 347 or Spicer equivalent?
.

 

[BSB67]

Does the case number actually tell us something about the u-joint size with certainty?

 

[Fran Blacker]

Maybe that it has a larger u-joint unless a 741 yoke can be put in a 742 case? In post #3 742 caseyoke with tape measure 7290 u-joint 1968? other 742case with yoke with centering tabs 1330 u-joint 1966/67 cars

 

[Belvedere13]

The original 741 2.93's came with the Wagon in a 5 gallon pail when I bought it as the previous owner upgraded to a new carrier with 3.55's but no Sure-grip. I was going to take the yoke off the spare 741 and use it but when I tried to put the 1 1/8" socket on the pinion nut it was a "No Go". I remembered reading on the Doc Diff website that if you have a 1 3/16" - 1 1/4" nut, you have a fine spline yoke...Scratch that idea. I contemplated using the pinion yoke from the 741 3.55's but that will negate the option of using it or selling it as a "ready to go" unit. With the 275/60 15" tires the 3.55's are like 3.23 gears accelerating and less than 2,900 rpm at highway speed. I'm hoping for a bit quicker "Launch" off the line .
Enough of my keyboard diarrhea for this morning...

 

[Belvedere13]

Fran Blacker...When it warms up a bit more here in the Once Great White North (a dig at our buffoon Prime Minister), I'll have to get serious about seeing exactly what I have to do to get the Wagon "smokin" the tires". Of course, with the Grand Daughter safely buckled in her car seat.

 

[Belvedere13]

The saga continues...I tried a 347 U-Joint only to find the caps are too large for the pinion yoke although it appears to be close in width. The other side seems to be correct as it fits the spare 741 yoke I have. The local supplier doesn't appear overly familiar with this yoke. The 742 yoke I have has the two "centering" tabs with a distance of 3.60" between them and an approximate opening for the cap of 1.04". Any assistance would be greatly appreciated.

 

[Fran Blacker]

That yoke takes outside clips the tabs are there to center u-joint. The u-joint with clips on cups are for 7260 or 7290 and others. If the tab to tab width of u-joint is 3.625" it takes a 1330 u-joint, cup size on that u-j is 1.0625". Does the driveshaft have outside snap rings? What is the width of u-joint on driveshaft, pictures.

 

[Fran Blacker]

Think this the u-joint you need but need more info on what is on your driveshaft and yoke to be sure, picture is wrong look at spec's. If your car had a 741 it's probably a 7260 u-joint.https://www.summitracing.com/parts/mog-457c/make/dodge

 

[Belvedere13]

Thanks Fran. Is the yoke OEM? The Parts guy said it was aftermarket because it has the tabs. Not sure about that. I'm not sure about the driveshaft yoke and it's still too cold to be laying underneath to check. I'm guessing it's the same as the spare 741 yoke I have which is OEM. So far my research suggests the Moog 457 may work for this application.
https://www.moog-suspension-parts.com/universal-joints-ujoints.asp

 

[Belvedere13]

Think this the u-joint you need but need more info on what is on your driveshaft and yoke to be sure, picture is wrong look at spec's. If your car had a 741 it's probably a 7260 u-joint.https://www.summitracing.com/parts/mog-457c/make/dodge

 

[1 Wild R/T]

First off, since 741 & 742 cases only use the 10 spline yokes & neither uses a crush sleeve yoke swaps shouldn't be an issue.... Second the standard way the measure joins is from cap to cap since there is significant variation in that dimension where as cap diameter variation is typically less than 1/8"...

Changing from a 741 to a 742 doesn't automatically require a different U joint, there are 741's around with the big yoke... And a few 742's with the small yoke...

 

[Belvedere13]

Fra...should have looked at your post before hitting "Post". Yes, I'm thinking the 457 is the one I need. What is the difference between the 457 and 454C? (Flush-type lube fitting in cross versus Regular Lube Fitting in Cross)

 

[Fran Blacker]

OEM Picture of my 66 742, Those yokes were 66/67 only but not positive maybe earlier. Tabs are hard to see look below cable on the left.

 

[Belvedere13]

First off, since 741 & 742 cases only use the 10 spline yokes & neither uses a crush sleeve yoke swaps shouldn't be an issue.... Second the standard way the measure joins is from cap to cap since there is significant variation in that dimension where as cap diameter variation is typically less than 1/8"...

Changing from a 741 to a 742 doesn't automatically require a different U joint, there are 741's around with the big yoke... And a few 742's with the small yoke...View attachment 924927

The OEM 741 carrier I have has an 1 1/4" pinion nut versus the 1 1/8" nut on the 742. According to the Doc Diff the larger nut has the fine spline and the 742 that I have that is rebuilt and ready to install has the course spline pinion.

 

[Belvedere13]

OEM Picture of my 66 742, Those yokes were 66/67 only but not positive maybe earlier. Tabs are hard to see look below cable on the left.
View attachment 924932

Fran....Yes that appears to be the same yoke I have. It came from a full size with 2.93? gears and sure-grip that I rebuilt and had Motive 3.73 gears installed.