64 Dart , any 8 3/4 rear differentials drop in no mods?

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Eworth

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Hello,

Just put a 318 in my 64 Dart. I do intend on pushing this Dart a bit and guess the 7 1/4 probably will eventually give out.

Are there any direct bolt in 8 3/4 Mopar differentials without modification?

If so, what years?
What stock gear ratios would have been available?
Any of these a "posi" or "suregrip" type as opposed to the "one legger" ?
How do I measure a differential to determine fitment?
How do I measure perches to make sure they are the same as my 7 1/4?

Pardon in advance for my ignorance. Please enlighten me. I won't be offended by the "dumbing down" required to teach a newbie.

Clueless, learning and appreciate any guidance. In the interim, will start looking for answers.
 
All A body 8 3/4 are bolt in. Drive shaft will need to be shortened. Use your emergency brake cables.
 
This answers a HUGE question of mine, thank you. To be cost effective. I can narrow to any A body. Thanks.

Are ALL A-bodies up to 72 all 5x4" bolt pattern? Were any of the B or C body 8 3/4 differentials 5x4 or were they all 5 x 4.5?
 
The 5 on 4s were an A-body only thing.
A-body spring perches are 43 inches on center. This also is exclusive to As.
If you are gonna run big meats, to run a reasonable backspace(affordable wheels), you will need to move the springs inboard, and narrow the rear to fit. So this means you can grab any bbp set-up, and cut it to fit.Now you have lots of wheel and tire selection.And you don't have to pay $10,000 for those super rare 74 DartSport 340 CL rears! I was gonna link you to it but I see the guy has pulled it.
 
Let's say I found an A-body 5x4 8 3/4 rear with 2:94 gears. What should I expect to pay for it, ready to install? I'm not sure what I should expect. Can you put me a price ballpark?
 
AJ/FormS said:
... If you are gonna run big meats, to run a reasonable backspace(affordable wheels), you will need to move the springs inboard, and narrow the rear to fit. So this means you can grab any bbp set-up, and cut it to fit.Now you have lots of wheel and tire selection...
Click to expand...

Be careful, Early A's have small wheel wells, not at all like 67 to 69 Barracudas or Dusters.
 
Eworth said:
Let's say I found an A-body 5x4 8 3/4 rear with 2:94 gears. What should I expect to pay for it, ready to install? I'm not sure what I should expect. Can you put me a price ballpark?
Click to expand...

Not sure what they go for but if you can bolt it in and go, you'd be done. They last forever. Check here and eBay for pricing.
 
Eworth said:
This answers a HUGE question of mine, thank you. To be cost effective. I can narrow to any A body. Thanks.

Are ALL A-bodies up to 72 all 5x4" bolt pattern? Were any of the B or C body 8 3/4 differentials 5x4 or were they all 5 x 4.5?
Click to expand...

The most direct bolt-in for you retaining the SBP is any 65-72 A-body 8-3/4". Direct swap except for the driveshaft. They are getting hard to find so I'd say a minimum price is $500 from someone who knows what it is. If you get lucky and find one in a boneyard, you could score with a lower price. Just a nice center section is probably going to be $400 and up. In the Mopar world it is "Sure-Grip" not "Posi". That's so GM.
73 and newer A-bodies went to the 8-1/4" with the LBP which is plenty strong for your 318. I have a buddy with a factory 73 340 4 speed with an 8-1/4" SG. 7-1/4" also available those years.

Only the A's had the 4" B.P. All B's and C's had 4-1/2".
 
Found a fellow with one described by me a couple posts up but it's not a suregrip. $750. I don't know, I could tear up a lifetime of 7 1/4s for that. Suregrip would be nice. Probably should keep looking
 
I just had Moser Engineering shorten a C body housing for me. Only extra was installing a drain plug. A little over $400 with shipping both ways. Worth every penny. High Performance adds up, but broken parts get old real quick. See if he will come down. The nice thing about an 8 3/4 you can change center sections in an hour or less.
 
65cudaVR said:
I was able to fit 215/60R15 tires in my 65 cuda using stock Mopar rally wheels.

I may have had to bend the wheel well lip slightly for clearance, otherwise no other mods...

Good luck!

'
Click to expand...

I think I've had wider, But I think AJ/FormS had a lot bigger than that in mind. I know you can put at least 10 inches of rubber in a Duster and assume the 67-69 Barracudas are the same. Maybe I'll measure the wheel wells on the 66 and the 67 Barracudas. Thanks for the input.
 
66fs said:
Be careful, Early A's have small wheel wells, not at all like 67 to 69 Barracudas or Dusters.
Click to expand...

Yeah, I knew that, lol,and that is why I don't have one anymore. The 400 or so pounds penalty in moving to a bigger-tub car, is offset by their ability to accept 325s in stock Plymouth Atubs. Plus a lot/most of the extra weight is on the rear axle,right where you need it. I think, IIRC, my current weight bias is around 51.5% front.
I sure do like the exterior looks of the early Barracudas tho. The insides;not so much.
I was actually responding to his statement of pushing it a bit. His cubic inch to weight is about the same as a 70Dart/360; and we all know what that can do. So I just jumped ahead to tires, cuz if you start "pushing it" with the skinnies, she will be swapping ends.Short wheel-base cars are fun that way, until you aren't expecting it, and then it's round-we-go in a heartbeat, and you are just along for the ride.
 
66fs said:
I just had Moser Engineering shorten a C body housing for me. Only extra was installing a drain plug. A little over $400 with shipping both ways. Worth every penny. High Performance adds up, but broken parts get old real quick. See if he will come down. The nice thing about an 8 3/4 you can change center sections in an hour or less.
Click to expand...

Whoa! You're pretty fast!
My best time is closer to 75 minutes, and that on a drive-on alignment hoist with air-jacks on both ends.And I was in my early 50s and pretty fit,too. Not like now........... :( lol
 
And it's a good point. At one time in the early 2000s, I had a row of chunks in pails . Everything from 2.73s to 4.30s, plus 4.88 and 5.38s. less 3.73s and traded the 4.10s for 3.55s. Plus spares. Most with SGs or Trac-locs. Swapping got old tho, so I bought a GearVendor and a low gear box. BaBam!

It's real nice to be able to swap chunks to see how the engine responds.
 
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