8 3/4 rear question

[Whitey]

My brother has an 8 3/4 rear out of an 68 Charger origionally a 318 car (honest). The center section has no markings or casting numbers on it. Has anyone ever heard of this? If so, what rear (pinion Diameter) could it be, 741, 742, or 489?

 

[69 Runner]

Never seen a carrier without a casting (read part) number on it. Theoretically it could be any of those, or any of the earlier carrier cases

 

[PettyBlue72]

I have actually ran across a similar center section in a local junkyard. It had no markings that denoted the case style or gear ratio.

Your case would most likely be a 741 case if it came from a 318 car. If the center section was original to the 68 Charger rearend, it will not be a 489 case as the 489 was not available in 68. I seriously doubt it is a 742 case as they were mainly for hi-po applications.

The best way to check the case is to measure the pinion diameter. 741-1 3/8 pinion, 742-1.75" pinion.

I hope this helps,
Joe

 

[440brew]

time to bust out the wire brush...

 

[Meep-Meep]

From my experience the 741 case was 67 and earlier, 742 was 68 or maybe late 67 (why only one year I don't know) and 489 was 69 and later. I would guess you have a 742. I have also seen casting numbers that were hard to read. like you said, brake clean and a wire brush!!

 

[PettyBlue72]

From my experience the 741 case was 67 and earlier, 742 was 68 or maybe late 67 (why only one year I don't know) and 489 was 69 and later. I would guess you have a 742. I have also seen casting numbers that were hard to read. like you said, brake clean and a wire brush!!

741 cases were used from 64 to about 72, mainly in A-Bodies and low horse cars. The 742 was used from 64 to early 69 and the 489 was used from late 69-74. I have seen a case with no numbers at all like I mentioned earlier.

Like I also said eralier, the best way to tell what you have is to measure the pinion diameter. I am betting it is a 741 case.

 

[ram250098]

I was looking at my Satellite the other day and did not see any numbers either, I belive it is a 8.25 rear as it has the 10 bolts on the back of the case.
They did not mark these like they do the 8.75s?
AL

 

[69 Runner]

I had a 70 340 4 speed Duster that was a 3.91 car (was sublime too) and it was a 741 case. Those gears ended up in my 69 Bee (numbers matching 383 auto) where they ran flawlessly for the 9 1/2 years I owned it. Car weighed 3610 empty and ran a best of [email protected]. No problems.

 

[PettyBlue72]

I was looking at my Satellite the other day and did not see any numbers either, I belive it is a 8.25 rear as it has the 10 bolts on the back of the case.
They did not mark these like they do the 8.75s?
AL

If the rear has a cover bolted onto the back of the center than it is an 8.25 rearend which not uncommon on 73-74 Satellites. No, Mopar did not mark 8.25's like the 8.75 rears. I am not positive but I think there was only one style of 8.25 rearend for the 60's, 70's and the early 80's.


Joe

 

[prhousejr]

my 68 satellite 318 has an 8 3/4 will have to crawl under to look for markings...

 

[Meep-Meep]

Every A 100 van we used to find in the junk yard had 3.55 or 3.91 with a 741 case and I never remembered seeing a 741 in late cars, but what you said makes sense about using them on low HP cars. It just doesn't seem to make sense from a manufacturing standpoint. Maybe left over stock and they wanted to use them up?

My buddy had a 3.91 741 in his 67 formula S 383 Barracuda and it went 12.0's on N2O and 8" slicks (11.84 @ 120 once at Fremont). Nothing puked out the back and he hit the button as soon as the foot went down.

 

[PettyBlue72]

64 was the first year for the bolt in axles and non-thrustblock 8.75 centers. The 741 was Mopars econo center for the 8.75. It was used in low HP, light-medium weight cars/A-100's(64-69) and A, B-Bodies(64 to 72). The 742 was used for high HP applications and in medium to heavy cars/trucks, IE B and C-Bodies and 64-early 69 fullsize trucks. The 742 suregrip center I have for the RR came from an early 69 Dodge truck rearend. The 489 was introduced in mid-late 69 and ran to 74 and was used in B, E, C-Bodies and trucks and possibly some late 72 340 A-Bodies since the 741 was being phased out. There are supposed to be some 489 cases made in mid to late 69 that had 742 ring and pinions along with the good Power-Loc Suregrip units. Mopar was using up leftover parts during the transition to the 489 case.

Joe

 

[Whitey]

If the rear has a cover bolted onto the back of the center than it is an 8.25. No, Mopar did not mark 8.25's like the 8.75 rears.
Joe

I have seen this rear...THIS IS an 8.75 rear, case pulls out the front, smooth back (no plate or bolts), non-sure grip. My bro used a putty knife to scrape the crud off it then used a wire brush trying to find numbers. NO markings. This was really a 318/904, 1968 Dodge Charger.

 

[prhousejr]

I hate being the noob, but could yall explain the pinion diameter numbers 741, 742, 489.........:sSig_noob: oh, and where would I find this marking?

 

[PettyBlue72]

Whitey,

We all believe you that you have an 8.75 center section that came from a 318 68 Charger. Also the statement about the 8.25 was in response to Al AKA RAM250098's post about his Satellites rearend and was not meant for you.

Like I said earlier, I have seen another 8.75 center with no markings like yours so I know they exist. We are just trying to compare notes to give you some info to help you determine what you have.

Good Luck and I hope you get it figured out

I'm Gone,
Joe

 

[PettyBlue72]

I hate being the noob, but could yall explain the pinion diameter numbers 741, 742, 489.........:sSig_noob: oh, and where would I find this marking?

The markings are usually found on the front of the center section. If you are looking at the center the way it would sit in the car, the numbers will be on the drivers side of the flat section just behind the yoke. It will be a long number that will usually end in either 741, 742 or 489(there are some other numbers for the cases but that is another post). Also on the same side on the round section you will find a large X for 741, a large 2 for 742 and a large 9 for 489.

As for the pinion diameters. This is the diameter of the pinion shaft itself. The 741 is 1 3/8", the 742 is 1.75" and the 489 is 1 7/8". The 489 tapers down towards the yoke threads where the other 2 are a constant diameter throughout.

I hope this helps,
Joe

 

[prhousejr]

thanks. big help.

 

[Whitey]

Wasn't bitching PettyBlue...just making the facts clear, sorry for the mixup.

 

[John Lang]

Petty Blue !!!! Your Wrong ! 64 was the last year for the tapered axles with the nut holding all together ! 65 Is the first year to use the slide in axle with the 5 nuts ! John Lang

 

[PettyBlue72]

Petty Blue !!!! Your Wrong ! 64 was the last year for the tapered axles with the nut holding all together ! 65 Is the first year to use the slide in axle with the 5 nuts ! John Lang

Sorry John, I was just going by the info I had which said 64 was the first year for the bolt in axles. My bad! Nobodies perfect.

Joe