67 rear brake drums

[Ron C.]

is this an original brake drum?

[Ron C.]

anyone know?

[1968RSZ28]

Ron -

They don't look like the original drums when I compare them to my Z.  My '68 Z/28 (I know you are working on a '67) original brake drums only have these "numbers" on them:

Right rear brake drum:  3841177     W-11X
Left rear brake drum:  3841177     W-1X

Also they have a slot in them for adjusting the brakes.  I don't see this slot in your photos, but then your photos don't show 100% of the brake drum.  Hope this helps.

Paul

[Jonesy]

I can look at mine, but right off the top those are not the correct originals. My 69 has the same 3841177 drums and they were used in later years also.

[Ron C.]

were the originals finned? mine dont look like gm drums and im thinking all gm drums are finned.

[rich69rs]

were the originals finned?

Not necessarily - my '66 Chevelle Malibu has non finned drums on all four wheels.

On my '69 RS the front drums are finned, and I have to doulbe check, but I am almost positive that the rear drums are not finned.

If I can find it, I have an AC Delco drum brake manual which includes intechangeability and part numbers.  Any other numbers other than the minimum ID of 9.590" and the G-10-454 number? 

In your second picture, you can see a "knock out" in the casting which is there to create the opening for adjusting the brakes.  I know that on the front finned drums on my RS that there are two of these knock outs 180 degrees apart.  One of them has been opened and has the removable rubber stopper in it so you can get to the star wheel on the brake adjuster.  The second knock out is still in place.   On your drums, is there a second knock out 180 degrees opposite of the one shown in the second pic?

[Jonesy]

They were not originally finned on rear drum brakes on first gens.

[Ron C.]

ok here is the other drum which I think is original because like you said it has 2 knockouts for brake adjustments,the other one doesnt.pic 1 is of the original I think pic 3 is the aftermarket one
pic1

pic2

pic3

[rich69rs]

From my previous post above:  If I can find it, I have an AC Delco drum brake manual which includes intechangeability and part numbers.

I did find my AC Delco Drum Brake Service Manual, 17D-11 from January 1971.  As it turns out, it just shows what applications used the same diameter drums.  1st Gen Camaros have 9.50 inch nominal diameter drums.  So you can look at the application lists in the manual to see what other GM applications also use 9.50 diameter drums.  However, nothing in this manual goes into the detail of finned or non finned, etc. and there are no part numbers listed - just drum diameters.