rear end original?

[whiskyman]

72 roadrunner, factory 400 car, want to know if rearend is original or correct, fender tag does not appear to show it, build sheet is missing the rearend info, is there a vin on housing?or some other way to tell? Car has a 8.25 now, with rubber ISO pads, car was built 9-30-71

 

[YY1]

2 barrel or 4 barrel 400?

What plant?

Thanks to a member here (69Coronetrt), I now have limited knowledge of Lynch Road axle codes.

I also found a source for the 71 LR engine and axle codes.
Not sure if all the axle codes continue in 72, as obviuosly the engine codes don't becuse of 383 vs 400.

 

[RustyRatRod]

Dang. I thought the ISO crud started in 73. Might be gonna learn somethin here.

 

[YY1]

You might be on to something.

Maybe something happened to the original axle (or someone took it if it was an 8 3/4), and the whole springs and all got replaced. How do the spring mounts look? Any rounded bolts or different weathering/rust patterns?

 

[RustyRatRod]

If I'm not mistaken, the axle has some numbers stamped on it that you can decode. I think they are on the axle tubes somewhere. They should be stampings. I don't know of a resource to look them up, though. I'll look online and see if I can find a reference.

 

[Moparlar]

It would have been an 8-3/4 without isolators. Isolators were not used till 1973

 

[whiskyman]

It's a 4 barrel, g= st Louis, nothing unhealthy to the eye about being sealed out, I just saw a 72 satallite sport 72, 400, with a 8.25, was told only 1 owner, so maybe not wrong after all?

 

[WP29440SE]

Dang. I thought the ISO crud started in 73. Might be gonna learn somethin here.

they did. 1973

It would have been an 8-3/4 without isolators. Isolators were not used till 1973

exactly

anything older was swapped

 

[YY1]

So the VIN is R?23P2G...?

I don't think "sport" was available past 1970.

I have a suspicion that the 8.25 may have been standard on 318 and 400-2 cars.
340 and 400-4 cars may have gotten the 8 3/4 standard.

I agree with the ISO theory- no ISO until 73.

Can you be a bit more specific about the car?
Some of your info doesn't add up.

The way I understnd it:

RL- Satellite (base)
RM- Raod Runner
RH- Satellite Sebring
RP- Satellite Sebring+

Engine code (5th Digit)-

M- 400 2 barrel
P- 400 4 barrel

 

[whiskyman]

fender tag

m21 n23 n41 r11 v8x end
vx4 u b41 b51 g11 l31
gb5 b2x9 tx9 930 111412
e68 d34 rm23p2g 125936

 

[Red63440]

When I bought my 63 I found that it had a 73 rear end under it with the isolators and the large spring plates. All of the geometry was thrown off and I almost had to use a hammer to get the rear shocks off due to the angle that the over sized spring plates had forced them to sit at. I ended up purchasing a set of original early style spring plates and eliminating the isolators all together. The main probem you will find is that there is a much larger hole in the spring perch that is welded to the rear end housing...I think its about 1 1'/4" in diameter compared to the 1/2" that your car came with.

I purchased new SS springs which had the 1/2" pins and ended up making two stainless steel reducers 1 1/4" x 5/8" thick with a 1/2" hole in the center. Once installed they are a captive fit between the rear end housing and spring plates and fit on the 1/2" sping pins perfect. Another thing I found out was that the 73 rear end housing is almost 4" wider than the housing that would have been in the car so if buying wheels I will need to allow for more back spacing....unless I change out the housing for a 66 or 67 housing.

 

[YY1]

See, it happens.

 

[YY1]

Sorry, no more help on axle, but bet that's a pretty car.

My P code 72 Charger has an 8 3/4 with 3.23 SG and a sway bar.

It's a Lynch Road car and the axle is coded at the top of the tag in a three digit number starting with 0. There is a list of 1971 LR codes on the 71 Superbee registry site.

Sorry I can't be more help.