Topic: 1970 428 brake drums Were they ribbed?

[ng8264723]

How do identify if they are original?

[J_Speegle]

Are you asking about front or rear brake drums?

[ng8264723]

Sorry Jeff
the rear.....

[rockhouse66]

I can't be positive about 1970 but in 1969 the Fairlane/Torino CJ rear drums had a rib on them but the Mustang ones are smooth.

EDIT:  Poor choice of words - the Fairlane/Torino rear drums are finned.

[specialed]

Are u asking about the groove as 69-70 has 1 groove  68 has 2

[ng8264723]

https://www.classicindustries.com/shop/1970/ford/mustang/parts/brakes/drums/#mz-expanded-view-1278830723401

THis is what i mean by ribs.  Mine are at my shop and I am home so no they are not exactly like this but the rib orientation is.  f they are original I will blast them.  I will look for a part number.  The car did not have a lot of miles so I thought they may be original

[Bob Gaines]

https://www.classicindustries.com/shop/1970/ford/mustang/parts/brakes/drums/#mz-expanded-view-1278830723401

THis is what i mean by ribs.  Mine are at my shop and I am home so no they are not exactly like this but the rib orientation is.  f they are original I will blast them.  I will look for a part number.  The car did not have a lot of miles so I thought they may be original

If ribs like on 2nd and 3rd picture then they are replacement .Groove around diameter like Ed mentioned but no ribs.

[J_Speegle]

For the rears I'm finding as others have posted. Many of the service replacements were produced with fins. Likely seen as an improved design so later parts could incorporate the change if specified in the bid.

For those reading that do have front drum brakes - like the CJ convertible in the unrestored picture thread - have found finned front drums used on that car and others during that year

[ng8264723]

Ok well that stinks.Does NPD have the correct ones?

[Mike_B_SVT]

Here are my original rear drums ~ '70 CJ Cougar, Dearborn, with Oct 6th build date (casting date on the drum is 9J10).

Kinda hard to see, but it has a single groove running around the outer edge.

[70cj428]

"I can't be positive about 1970 but in 1969 the Fairlane/Torino CJ rear drums had a rib on them but the Mustang ones are smooth.

EDIT:  Poor choice of words - the Fairlane/Torino rear drums are finned."

+1, I've been researching and documenting 1970 CJ Mustangs since the 1980's I'm 99.999% certain that Mustangs came with single groove , non finned rear drums. The finned rear drums work on a Mustang but seem to be original equipment on the Torino/Fairlanes.

[Anghelrestorations]

There is no accurate reproduction or replacement rear drum that looks like the originals...to answer the original question.