Front Drum Size Question

[erik70rt]

Would a 383 powered R/T have the same front drums as a base 318 car? 

[anlauto]

I would think so I was under the impression that all E Bodies used the same size ? Maybe six cylinders were smaller ???

[JS29]

@erik70rt I don't believe they do! A 383 R/T would come with 11" drum brakes, A 318 car should have 10" drums. 

[anlauto]

See...there you go.....I was just looking it up for shits and giggles and found the same info...JS29 beat me to it

[ec_co]

the slanty has 10" too

[RUNCHARGER]

Nope: The R/T came standard with 11 inch drums. 10 inch drums on standard Challengers. Not sure if a standard Challenger with the optional 383 4 bbl came with 10 or 11, Dan will probably know.

[6bblgt]

1970 E-bodies:
BH, BP, JH
STANDARD drum brakes
10x2-1/2" front drum w/10x2-1/2" rear drum (POWER Brakes "B51" OPTIONAL)
   *** OPTIONAL HD drum brakes ("B11")
   ***  11x3" front drum w/11x2-1/2" rear drum  (POWER Brakes "B51" OPTIONAL)
   *** OPTIONAL disc brakes ("B41")
   ***  front disc rotor w/10x2-1/2" rear drum (POWER Brakes "B51" MANDATORY)

BS, JS
STANDARD HD drum brakes ("B11")
11x3" front drum w/11x2-1/2" rear drum  (POWER Brakes "B51" OPTIONAL)
   *** OPTIONAL disc brakes ("B41")
   ***  front disc rotor w/10x2-1/2" rear drum (POWER Brakes "B51" MANDATORY)

* 4.10 DANA60 cars ("A32" & "A34"): BS, JS w/440HP, 440+6, HEMI only
the 4.10 axle package included disc brakes ("B41")
  ***  front disc rotor w/10x2-1/2" rear drum (POWER Brakes "B51" included)

* TRANS AM cars ("A53"): BS AAR & JH T/A
the "A53" package included HD disc brakes ("B42")
  ***  front disc rotor w/11x2-1/2" rear drum (POWER Brakes "B51" included)

* 340 rallye package Challengers ("A66"): JH only
the "A66" package included HD drum brakes ("B11")
11x3" front drum w/11x2-1/2" rear drum  (POWER Brakes "B51" OPTIONAL)
   *** OPTIONAL disc brakes ("B41")
   ***  front disc rotor w/10x2-1/2" rear drum (POWER Brakes "B51" MANDATORY)

[6bblgt]

the larger HD drum brakes ("B11") were NOT included with a 383 in a BH, BP, JH car

& "B51" on a fender tag is the code for "POWER BRAKES", a '70 fender tag does NOT distinguish between DRUM & DISC

[JS29]

My BP 383 D21 4-speed has 11" rear drums. It has a disk brake conversion on the front. So i have to believe that this car came factory with 11" front drums. 

[6bblgt]

B11 "HD drum brakes" were a $22.65 OPTION on the Gran Coupe (BH & JH, too)

~10.4% of the '70 Gran Coupes had "HD drum brakes" factory installed 

[JS29]

B11 "HD drum brakes" were a $22.65 OPTION on the Gran Coupe (BH & JH, too)

~10.4% of the '70 Gran Coupes had "HD drum brakes" factory installed 

Yes but My car from my understanding came with the 383-HP because it came with a 4-speed. The same as a base 'cuda. It would make sense that my car would have came equipped with 11" drums as standard BS's would?  

[6bblgt]

the upgrade from 318 to 383 4bbl (383HP w/manual transmission) in a BH, BP, JH
did not include upgrade to the brakes or suspension - they were available for additional $$$$