Is 8 3/4 standard or not ?

[skip68]

I just found out that my rearend is a 8 3/4.  My fender tag says I have 276 gears but doesn't tell me the rearend size.   My question is did my rearend get changed at some point or did the 68 base model 318/auto come stock with the 8 3/4 276 rearend? ?   Thanks,  Chuck.........

[daves68]

Chuck- Yes they did. I also have the same car/engine combo as you  and it still has the original 8 3/4-276 set up.

[8WHEELER]

   8 3/4 was what you got is a 68 charger, the stock slant six cars I have seen up to Hemi auto cars had them as well.

Dan

[skip68]

Thanks guys, I thought I was going to have buy a 8 3/4 until today... Now all I have to do is get a sure grip I was really worried that the built up 446 I have was going to scatter the smaller rearend....Oh Dave, did you keep the 318 or put a 440 in it ? If you did the swap, how does it run (off the line)  Thanks again,  Chuck................

[Rocky]

Make sure you check out the number on the housing though.  there are 3 different types, and the ring gears are different for all.


My 68 318/auto 2.73 came with a 741 case.  this is generally considered the "weak 8 3/4".  Ring gears are pretty hard to find for this case, so you might think about making a change.

The good news is that you just pop out the old pumpkin and swap in the new one.

[daves68]

Chuck- I still have the original 318 although I did have it redone and built somewhat several years ago. Now, the entire car is in a major renovation and will be receiving a 440. I intend to keep the 8 3/4 rear as it has 3.55 gears and will be just right for the  road trips in my futue.  Rocky is correct too. There are 3 types of center sections, cast into the side are the numbers 741, 742 or 489. The 741 has a smaller pinion and is the lighter of the three. However, your intended use will dictate which one yoou use. Since I won't be beating mine down the racetrack, the 741 is OK. I will get the sure grip addition though. Aftermarket gears for this size are available, but I have not found a ratio lower than 355. Good luck with yours. Dave

[694spdRT]

It will probably be a 741 or 742. If memory serves me the 489 case first came out in 1969.

[skip68]

Thanks again.  Well, I guess I'll have to go back out and jack up the car again and find the numbers. I'm not going to beat my car but I do want the sure grip and to have a track day or two.  My 446 should be in the 500 H.P. range so I've got to be carefull. I should get a dana 60 but I'm just not going to run the car that hard. Again, thanks and good luck with the 440 Dave.

[skip68]

Well, I looked at my rearend and it is the 741.  That sucks bad.!!!  So I guess I'll be looking for another rearend soon

[RD]

there is nothing wrong with the 741 case.  I ran one for two years in my drag car (71 charger 12.17 1/4 mile times) and she took every bit I could throw at her.  They say the 741 is weak because of the pinion diameter, but that is not where most 3rd members break.  They mostly break at the main caps and the gears themselves.  Do not sell that 741 case for not being worthy.  It will handle alot of abuse.

[skip68]

Thank's for the info RD.  Then should I leave it alone or do a sure grip.?

[daves68]

Get a sure grip unit- with that HP, you'll be glad you did. I have seen advertisements about a new sure grip unit from Detroit Locker. Instead of clutches and cones, it has a set of parallel helical gears that provide the no slip function. Don't know if there is one for Mopars yet but I am going to research it and find out. Try checking with Summit, it's in their new catalog. Dave

[skip68]

Thanks Dave,  I'll look into it as well    Chuck...