Rear brake size on 70 Challenger R/T 440 car and min thickness?

[Marksmopar1]

 Hi,

I have looked ever where and I am unable to find the correct size of drum brakes that should be on a 70 Challenger 440 auto with power disc and rear drums.
  One old article I read said 10" drums on the rear if power disc was ordered? But I read other specs that say 11" drum should be on the car.
  I ask because it looks like some parts were "scavenged" off my car some where some time by a past owner...the brakes are 10" on the rear now, I think 11" should be there, unsure?
  As well, it seems only 4 leaf spring are on the car L+R..now I know that is incorrect.

Any insight is much appreciated....

[RUNCHARGER]

Yup 10 inch rear drums with front disc on a 440 Challenger.

[Marksmopar1]

 Thank you!

He's is one more question...the 10" drums have no Min thickness measurement cast into them and I can not fin what this measurement is?
Would you know? I have looked in all my books...normally the number is cast onto the drum..not on these?

  Thanks

[Brads70]

I find rockauto is also good for info like that, Looks like .060"-.090"?  over is the discard size?  Seems 11" is also common though?
https://www.rockauto.com/en/catalog/dodge,1970,challenger,7.2l+440cid+v8,1495993,brake+&+wheel+hub,drum,1744

[MoparDave]

depends on how the car was built. check your build sheet if you have it.  My 70 Rt SE 383 has 11 drum/drum

[RUNCHARGER]

Yup: 11 inch drum, drum. With a 383, 440 or Hemi R/T or Cuda if you went to disc front you got 10 rear.

[Marksmopar1]

 I do have the build sheet

B41 + B51 But this does not tell me the rear drum size. This leaves me to literature research... and even that says HD brakes 11"? But I have seen posted 11" rear drum with front drum. Front discs received the 10" drum. Still many sources say 440-440+6 and Hemi received HD brakes calling 11" drums with disc... confusing

   To top it off, my leaf springs have 4 leaves....that is wrong has to be, no numbers anywhere on those. So my guess is they were robbed off the car at some point. This is why I question the drums. The 15X7 rallye wheels were missing (had 14" on it) steering wheel had a 73 year wheel, rear valance was a 71+up, some parts were "borrowed".
   
At least the #'s match, rad/ carb/ manifolds / engine + trans....all the main items. I am questioning everything on the car.
This is my first E-Body I normally build B/RB A-Bodies and I have 3 of them, so I know them well but E-Bodies are a bit different and have some interesting quirks as all car lines do.

Appreciate the answers as I learn more on these cars. I did question the number of leaves, anyone now how many should be on this car? I know L+R short leaves had the #'s on them. 

Thanks!

[anlauto]

B41 is front disc with 10" drum,

B42 is front disc with 11" drum (like AARs/TAs)

[Marksmopar1]

 Ok, Thanks!

Looks like 10" rear drums it is and it has....

  Anyone have info on the springs? How many in the stack for a car like this? I have only 4 springs L+R side.
I will be doing springs as this seems to me to be an insufficient number of springs to me.... Curious as to what was in the car or should be?

Thanks again!

[anlauto]

Is your car a "U" Code 440 car ?
Is there part numbers on the short leaf at the bottom ?

[Marksmopar1]

 Hi,
Yes U code car...and the short leafs with the P#'s are not on the car...just 4 leaf springs and not even a clamp on any of it to hold them together.
   I know it's all wrong but I am curious as to what should be there and what it should look like...

[anlauto]

Do you have a broadcast sheet ?

[Marksmopar1]

  Yes I do have the sheet
rear spring 034(LT) /  024(RT) The car is A01/A36/ A62 optioned

I know these are the 440/440+6/ Hemi spring and of course someone robbed the two small springs with the P#'s on them.
But, how many springs in total would/ should the car have with this spring option? Same number of springs on Left and Right?
  I know they sell the P# shorty springs repo...but no I have no idea how many springs in the spring pack originally.
 
Appreciated!

[anlauto]

Okay, so with #024 and #034, counting the leaf with the part number, at the rear axle there should be six leafs per side. Also those springs have a smaller diameter front bushing.

[Marksmopar1]

 Anlauto,

  Thank you very much!  This is what I was looking for. The answer seems a tough one to get!
The springs on my car have obviously been raped. I will build them to specs now that I know what was originally on the car.

As for the 10" drums, these have no Max Dia. on them, nothing stamped pr cast in. So I am going with what I have seen on aftermarket replacements figuring the drums must be cast the same to fit? 10.090 is what I am using for Max Dia. The drums are 10.030 / 10.040 so very usable IMO.

  I appreciate the help, fellow Canadian I see    Gas carbon tax hit today...this sucks. Building and enjoying our cars is getting more expensive by the hour it seems.

Thanks!