8 3/4 Help

[c_callen]

Need a little help before I jump into a gear swap. My 64 Polara has a 741 with crazy high highway gears right now. I just lucked into a 742 with 3.91s and a sure grip. I know the third member will bolt right in but what will I need to warn out for. I'm under the impression that I'll need a bearing kit and that the axles might need to be swapped out too. Thanks

 

[mmissile]

For ease of future work on the rear/update. I'd find a housing and axles from a 65-67.

 

[1967coronet440]

Need a little help before I jump into a gear swap. My 64 Polara has a 741 with crazy high highway gears right now. I just lucked into a 742 with 3.91s and a sure grip. I know the third member will bolt right in but what will I need to warn out for. I'm under the impression that I'll need a bearing kit and that the axles might need to be swapped out too. Thanks

What's the splines on the axles, and the new third member?

 

[skicker]

Could always call Dr Diff and order axles from him with green bearings...
Source a set of 10" backing plates and drums from a 65 up and eliminate the earlier set-up.
You will be upgrading what you have while picking up the 3.91 gear.
Also check the yokes on both rears as you may also need a conversion U-joint if they are not the same... .02

 

[c_callen]

Iok count the splines on the 742 this afternoon. Hadn't done that yet. The last rearend I did was a gm 10 bolt so this is uncharted territory for me

 

[1967coronet440]

Iok count the splines on the 742 this afternoon. Hadn't done that yet. The last rearend I did was a gm 10 bolt so this is uncharted territory for me

Do yourself a favor and give doctor diff a call, you won't be disappointed.

http://www.doctordiff.com/

 

[c_callen]

I just counted the splines and came up with 30.

I'll give Diff Drs a call tomorrow. Thanks guys

 

[1967coronet440]

If you need the backing plates and drums shoot me a message I have a set for a 67 8 3/4, also as mmissle said for future ease of work if you want to upgrade the housing i have the axle housing and axles if you're interested.

 

[Glenwood]

The research I've done on this topic for my 64 points to shorter axles when a suregrip (SG) is installed on a non-SG rearend for pre-64 8-3/4. That should mean the 64 axles are ok to use. I was thinking of proving this with my 489 SG since the rearend is out of the car, but it's out getting the gears swapped.

 

[skicker]

I may be incorrect about this but when I talked to Cass (Dr Diff) I think he said you need to remove the buttons in the center section when use a sure grip to fix this problem. I just ordered a custom set from him a few months back for a 65 housing we put in a 72 Duster. We're using Wilwood rear discs and did not need the plate installed between the bearing and the axle flange as it is incorporated into the Wilwood caliper bracket mounts. I think he has these axles in both lengths...with and without buttons...
You do not have to replace the 64 housing once you change the axles and backing plates but it does require purchasing new axles and 65 up brake assemblies.
I had researched this some a while back. I have a 65 housing for in my AWB 65 Coronet. The older slots I have for the rear have a little more dish towards the outside. I called and talked to Cass about getting a set of axles for a 63 housing I had from a parts car as it is exactly one inch shorter in overall length. I can order those axles and use the 65 up rear brakes and shorten the overall rear 1" for just the cost of a set of axles...
Definitely talk to Cass as it seems he has a way to make almost anything you need to do work out.

 

[Glenwood]

If it is a cone type SG, it does not have thrust buttons, but rather a thrust block on a pin I believe. I asked Cass about this when discussing the green bearings he sells which requires removal of the buttons on clutch types but doesn't affect cone types. So maybe the 64 axles are okay? I've read pulling the tapered axles out can be a chore as they require a slide hammer tool?

 

[skicker]

The 64 back axle removal is no problem if its a rear where you are not reusing the 64 hardware. (brakes, axle and backing plates)
The 63 I had was in rough shape so I cut the drum around the outside of the axle and removed the drum that way. Once removed the 5 axle bolts are the same as a later 8 3/4.
The axle puller is required when taking it apart the correct way by removing the large nut and cotter pin. The axle itself is a two piece design that has a tapered key-way. The 64 back axles are actually a two piece unit.

 

[c_callen]

Anyone have a phone number for dr diff? Tried calling but it says not in service

 

[1967coronet440]

I called last week to order my Dana using the number on the site