8¾ gear swap questions

[big_shmoop]

My car currently has 2.94 open diff in a 742 housing. This off season I was hoping to swap it out for something a little a taller for a little more "umph" off the line.

There is a local guy who has an open 3.91 in a 741 housing that I'd be able to get my hands on pretty cheap and was thinking it would be nice to try it out. Is there anything else I'd need to do the swap or will the driveshaft hook right up?

Ultimately since I'm looking to do a aggressive street/some strip car I'll be looking to do a full rear end build with a 489 case and upgrade axles, so this will just be to try things out and hold me over. Seeing how it easy it is to swap I figured why not.

Thanks.

 

[GTXperience]

Check to see if you both are running the same size u-joints. Otherwise, enjoy.

 

[PRND21]

Unless somebody has changed the yoke, it should bolt right in.

 

[big_shmoop]

Thanks for the feedback guys.

Unless somebody has changed the yoke, it should bolt right in.

Are the yokes shared on all three housings or is the 489 different?

 

[Fran Blacker]

You need to compare the yoke/u-joint from the two third members. There are a ton of adapter u-joints out there. My bet is the 741 has a 7260 yoke and the 742 is a 1330. There are adapter u-joints for this combo. The picture is a 7260 yoke 3.25" appox. and has inside clips to hold cups in place.A 1330 yoke is 3.75" but has small tabs to hold the u-joint cups on the outer ends of the yoke cup mounts so the u-joint is 3.625" and 1.0625 cups. then there are other u-joints 7290 and 1350. I adapted a 7290 yoked driveshaft to a 1330 yoked Dana 60 by taking the 7290 cups off and putting on 1330 cups. You can find u-joint dimensions online.

 

[big_shmoop]

Excellent info, thank you.

 

[Fran Blacker]

Excellent info, thank you.

Your 742 is in your 67 Satellite I assume. In 68 I think they when to the 7290 as there BB u-joint. Could be wrong. The 7290 drive shaft I wrote about was from a 68 Hemi GTX 4 speed I ran it but the shaft was to short to be right. I have a 66 Satellite it in my picture.

 

[Fran Blacker]

Did a search a search about 8.75 rears but did a typo and canup with a site that had go info, there's probably a million of them. The typo I put in "gig" instead of "did".
search what year gig Dodge start with the 489 rear axle housing. Then click on Chrysler 8 3/4 axle guide- Tripod.
That site didn't come up if I spelled "did" correctly.

 

[big_shmoop]

Did a search a search about 8.75 rears but did a typo and canup with a site that had go info, there's probably a million of them. The typo I put in "gig" instead of "did".
search what year gig Dodge start with the 489 rear axle housing. Then click on Chrysler 8 3/4 axle guide- Tripod.
That site didn't come up if I spelled "did" correctly.

I think I found it: http://members.tripod.com/~Mojo_Page/chry875.htm

Thank you again, this helped immensely.