education on the suregrip as it applies to 1964 dodge 440

[mosquito13]

car came with a 318 poly , 727 pushbutton going to a open rear 8 3/4. has the tapered axles. so what info do i need to determine to get a working suregrip in it? suggested gearing . i have a mild built 440 and a b/b 727(pushbutton) and drive shaft out of a 65 cornet that is rebuilt with a stage III transgo shift kit. primary use will be commuting as a hooligan to work (7 miles and 11 stop lights) and occasional highway. no strip . gas and tire economy not a concern...



and as a thank you for your help enjoy : http://www.mcrfb.com/files/commericals//Spots Detroit Dragway 64.mp3 radio spot for big daddy at detroit drag way

 

[5.7 hemi]

Just swap in a sure grip in place of the open carrier or swap the entire center chunk with one that has a sure grip. Gearing is a personal choice and tire size will play a factor.

 

[mosquito13]

no difference in the axles splines ?

 

[chignikred]

splines are not the issue. AXLE lenght of an 'early' between a non posi center and a posi is the issue. Suregrip axles are shorter, and would have to be cut down using your existing axles. you can search the web and all the dirty details on this.

Make life easy and find a 65 to 67 complete rear end and swap.

 

[Cranky]

Don't know how much work you've done on a tapered axle rear but one of the things I like to do with them is replace them with the later 65 up units. Much easier to work on especially if you don't have the proper tools for them.

 

[mosquito13]

Yes i am vested in the tapered rear , doing the conversion written up be member Centerline(big thanks). Just need to take 'em to my buds shop and press out the old , seperate , and put in the new . rebuilt the brakes yesterday. So i would rather not scrap the time and $ invested in this set up. Back to the question at hand, what sure grip unit will work with what i got? There is one from a 64 on fleabay. Just waiting on a answer from the seller if the car had tapered axles and if he also has the axles. auction #290821419599. ends tonight... Anyone able to shed more light before i drop more $$. not finding much info on cutting the axles down. three googles down .

 

[Cranky]

Well, that one doesn't have the thrust pin in the center.....which is pretty common in the clutch type SG's. Also, the ring gear is pitted. It could be ok but on the other hand, it might not be. I've run em before that looked that bad and they were ok. Generally, pitting occurs when it's been sitting in a junk yard for years and the oil drains off the top half and moisture takes over.

 

[Centerline]

I can't personally vouch for this information but it comes from the Mopar 8 3/4 Axle Guide. According to that info the differnce in axle lengths was prior to '64 only. 1964 and later sure grip units used the same length axles as the non sure grip. I've posted the relevent section of that guide below.


Section 1: Thrust Block Variations

There was a difference in thrust blocks prior to 1964 that make center section interchange, as well as axle interchange problematic. The thrust block, or "axle shaft thrust spacer", it thr block that both left and right axles butt up against inside the center of the differential. Prior to 1964, all open differentials used a thrust block was approximately 1/8" to 1/4" thicker than units made after 1964. The Sure Grip thrust block prior to 1964, however, was indentical to all 1964 and later Sure Grips and open differentials. In 1964, the thrust block width was changed to match the Sure Grip thrust block width.

This difference in thrust blocks between Sure Grip differentials and open differentials required that two different axles be produced for each 8-3/4" housing manufactured. This is true of all 1959-1963 cars with 8-3/4"s.

A 1964 and later differential, or any Sure Grip differential, cannot be used with 1959-1963 rear ends and axles originally equipped with an open differential. The original axles must be machined or original Sure Grip length axles must be used.

 

[SuperFlyTNT]

To further address the info above posted by Centerline; I have put the 3.55:1 3rd member from a 64 Polara in my 68 Satellite without any issues. It is an open carrier, so at least for my case the abovementioned info can be regarded as 'true' for 64-up. So, if you have an open carrier in your 64 and you go to a sure grip, the axle shaft length should not be a problem.

SuperFly TNT

 

[mosquito13]

Centerline and Superflytnt good info and feeling better about dropping the cash on a suregrip. Pretty sure on the answer , but please confirm : Are all 8 3/4's set up for thirty spline axles?
Appriciate all advice to this mopar newby. Cranky thaks for the eval. , someone with the ebay handle "a**a" out bid me with two seconds left ... should have used auction sniper myself.

 

[Centerline]

The Mopar 8 3/4 Axle Guide (posted on the 62-65 web site) says,

"Interchange Notes:
Any complete 8.75" carrier will interchange with another 8.75" carrier in any 8.75" housing. The Sure-Grip assemblies also interchange. However, none of the other separate parts such as cases, pinions and bearings will interchange."

That tells me that all the axles will have the same spline count. Could be wrong, but I don't think so.

 

[5.7 hemi]

All factory 8 3/4's are 30 spline.

 

[emore]

I know you say your committed to the tapered axles, but with a little bit more power, it wasn't uncommon to shear off the key-way in the hub. a switch to a 65-70 3rd member might be a good investment.

 

[Centerline]

I know you say your committed to the tapered axles, but with a little bit more power, it wasn't uncommon to shear off the key-way in the hub. a switch to a 65-70 3rd member might be a good investment.

If I was going racing I would switch. However, Chrysler felt their tapered axle 8 3/4 diffs were strong enough for the Max Wedge cars so as far as I'm concerned, for a primarily driven street car there's really no reason to swap. Many don't like them because they believe they're difficult to service, but with the brake conversion servicing is just about as easy as any later model.