71 roadrunner 8 1/4 diff

[polywideblock]

when I bought my roadrunner ( 340 4 speed ) the guy I got it from said the car still retained the "original " running gear, said something about a shortage of 8 3/4 diffs at the St. Louis plant and it had a 8 1/4 possi diff that he said was a 3:23 ratio . I want to keep it original if it belongs to the car so the big question is would a 71 340 b body come with a 3: 23 possi 8 1/4 diff? its a late build date (504) with a lot of 72 parts

 

[dasol7172]

IRC didnt the St. Louis cars have the rear listed on the data plate?

 

[Kernel Sanders]

My guess is your gonna need a build sheet to know for sure but its certainly possible

 

[polywideblock]

no diff info

 

[YY1]

What's "A87"?

 

[polywideblock]

roadrunner décor package

 

[Car Nut]

Does this help?

 

[polywideblock]

already know its an 8 1/4

 

[dasol7172]

Its possible.. I have a 71 SSP that came with a 318/904 to a 8.25 that was OEM.

 

[Cameron Wilson]

Did 8 1/4 even come with 3:23 ratio? I thought that was a 8 3/4 ratio. New to this so forgive the ignorance

 

[Car Nut]

already know its an 8 1/4

In a 71?

 

[Darter6]

I have found 8 1/4 rears in B bodies in a 69 Satellite and a 70 Coronet.Both 1 owner cars.I do know that a 3.21 ratio was available in the 8 1/4.

 

[Bb70charger500]

It's possible but if there's no codes for it don't worry about it as it should of had the 8 3/4 I've seen a bone stock never touched car 440 727 8 1/4
The owner swore up and down it's never left his sight and he didn't touch it . so you never know but to be correct 8 3/4 because it's correct!

 

[YY1]

I'm fairly certain the 8 1/4 was not available in 1969. 7 1/4 or 8 3/4 (or Dana)

 

[moparmarks]

I've had 69's with the 8.25

 

[YY1]

I might be thinking 67.

Every 66 I've had as had an 8 3/4 but my 67's are 50/50 8 3/4 or 7 1/4, but no 8 1/4.

 

[moparmarks]

I think 69 was when they started using the 8.25 in the B's.
Every 68 and older that I've owned had the 8.75.
In 71 they used the 8.24 in B's more often than before.
I have a 74 Coronet with a 400 4-bbl and a 8.25.
All 71-73 HP B's should have the 8.75. I think it is possible that they may have been short on 8.75 and through in an 8.25 instead. Hard to know for sure without the broadcast sheet.
I'd be looking for an 8.75 to put in it.