getting an 8 3/4 from a 69 dart

[nutz]

its a small lug out of a 69 dart is all i know
going to swap my 7 1/4 out
is the gear ratio stamped someplace and date code (not that it maters)
i know nothing about it other that was out of a gts
thanks nutz

 

[junkyardhero]

gear ratio is stamped on the ring gear. no outward ID. *unless* the gear tag is still on the diff. it's a small metal tag that's under one of the center section attaching nuts. but even then, it may or may not be that gear.

turn the axle and watch the yoke and count the turns to figure out what you've got.

if he's got the e-brake cables and shock plates grab those too. you'll need 'em as well cuz theys different than the 7.25

buy new u-bolts

 

[66fs]

His emergency cables in the car should work. Get the driveshaft if you can and get the U-bolts also. The drive shaft is a different length. Sure grip wheels spin in the same direction, gear ratio should be 3.23 but who know what it is now.

 

[nutz]

hope its a 323 sure grip ,all i saw was 10" drums and cables...

 

[JDMopar]

Next up, a guy telling you ALL 8 3/4 A body rearends have forged axles....

Sounds like a good score...glad you found it!

 

[missing linc]

There would have been a small metal tag attached to one of the studs originally, but after 55+ years it could be long gone.

 

[nutz]

no tag new brakes ,didn't measure the drums but look worn
its a sure grip ...yea
ill pull it apart anyway (looks like new seals) and clean reseal then check the ratio
no tag

 

[JDMopar]

You don't really need to pull it apart to determine the ratio unless you just want to. Set it up on jack stands, blocks or something, with the yoke sitting level. Move the yoke so it is pointing vertical, and mark the top so you can see it easily...blue masking tape maybe. Mark the top of one axle flange too. Now, just turn the axle slowly, one complete rotation until your axle mark is back to where it started. But, as you turn the axle...count how many turns the pinion yoke makes in one turn of the axle. If it turns 3 1/2 times, you have a 3.55 gear, 3 1/4 times...3.23 gear, just shy of 4 turns...3.91 gear. Hope that makes sense?

 

[junkyardhero]

Next up, a guy telling you ALL 8 3/4 A body rearends have forged axles....

Sounds like a good score...glad you found it!

only if they were built in michigan!

 

[nutz]

Oh yea I know that
I wouldn't put it in without opening it up
But might (count) it just to know
It has a crappy silicone seal job anyway

 

[crackedback]

It has a crappy silicone seal job anyway

Works better than the gasket a lot of times. I never use a gasket on them after having a few leakers

 

[nutz]

yea i use ultra black ,never leak ,the stuff that is on here looks like the black from the 80's clear with a black tint

 

[nutz]

f-me think its a 4 :56 ,way too low for me
3 :55 /or 3:23 is what i'm looking for
i'll pull it this weekend to make sure

 

[cosgig]

f-me think its a 4 :56 ,way too low for me
3 :55 /or 3:23 is what i'm looking for
i'll pull it this weekend to make sure

What case number is the center section? That will help you when looking for gears.

 

[nutz]

Ill check when I pull it apart
I did a count yesterday
Looked like 4.5 .....
Much lower than I want

 

[JDMopar]

<------ Waiting on the big fat ring gear pics! lol

 

[nutz]

4:10....still too low for me
not sure what type of posi unit
someone has been it there
guess i'm going to sell p/m me if anyone is interested
looking for a 355 /or 323 /could go 373
from that one pick looks like a chipped gear ....will look tomorrow

 

[George Jets]

Can tell that is a very deep ratio by how thick the ring gear is.

A 3.23 ratio is about 1/2 that thick.


☆☆☆☆☆

 

[nutz]

so i want a skinny gear for top end
fat gears are pigs on gas............

 

[john-9]

you have a factory cone style sure grip ,, probably needs a rebuild for sure with that gear ratio on it ,, pics do not show if the center pin has worn into the case which would mean the spider gears have welded themselves to the cross pin , sheared the locating pin and ruined the case .

 

[George Jets]

so i want a skinny gear for top end
fat gears are pigs on gas............

The '69 Satellite 318 that I owned came factory with an 8 3/4 rear end, with factory 2.94 gears > 741 case.

I added an Edelbrock 1406 4 bbl, and the light weight Torq Thrust II wheels which also helped with the gas mileage.

Took off the gas leaking, fire hazard original BBD 2 bbl.

20 miles per gallon with that one running the Stock '69 318, 9.2:1 cr, 230 horsepower original engine.

2.94 is my favorite gear set. Performed nicely, and I could pass anyone I wanted to going down the freeway at 70 - 80 mph.

Also by chance my '89 Truck that I have now also has a 9.2:1 cr 318 engine with added 4 bbl.

Rear end is a factory 8 1/4 with the 2.76 gear set, like that too for my driving habits and good gas mileage.

Performs nicely even coming off the stoplights.

Here again the light aluminum wheels help performance and gas mileage too.

___________

Even with a 3.23 rear gear ratio, at today's freeway speeds, a person's engine will be winding to beat heck keeping up with 80 mph traffic.


☆☆☆☆☆

 

[nutz]

you have a factory cone style sure grip ,, probably needs a rebuild for sure with that gear ratio on it ,, pics do not show if the center pin has worn into the case which would mean the spider gears have welded themselves to the cross pin , sheared the locating pin and ruined the case .

is there a way to tell without taking apart

 

[nutz]

The '69 Satellite 318 that I owned came factory with an 8 3/4 rear end, with factory 2.94 gears > 741 case.

I added an Edelbrock 1406 4 bbl, and the light weight Torq Thrust II wheels which also helped with the gas mileage.

Took off the gas leaking, fire hazard original BBD 2 bbl.

20 miles per gallon with that one running the Stock '69 318, 9.2:1 cr, 230 horsepower original engine.

View attachment 1716363646

2.94 is my favorite gear set. Performed nicely, and I could pass anyone I wanted to going down the freeway at 70 - 80 mph.

Also by chance my '89 Truck that I have now also has a 9.2:1 cr 318 engine with added 4 bbl.

View attachment 1716363647

Rear end is a factory 8 1/4 with the 2.76 gear set, like that too for my driving habits and good gas mileage.

Performs nicely even coming off the stoplights.

Here again the light aluminum wheels help performance and gas mileage too.

___________

Even with a 3.23 rear gear ratio, at today's freeway speeds, a person's engine will be winding to beat heck keeping up with 80 mph traffic.


☆☆☆☆☆

not that its going to be driven that much ,but anything in the twos are a little high foi a 4spd still need some giddy up

 

[66fs]

3.23s would be perfect.

 

[junkyardhero]

3.23's

this is the way.