On my car, original drum brakes are mounted on the rear axle. one of the drum was still the original shape, the other one had already been replaced with a different type (which still fitted mechanically). The part number of this drum was C-2263 (manufacturer: Centric). Attached some pics of my previous setup:

Original brake drum (left side)


Replacement Centric C-2263 drum (right side)



Detail view of replacement Centric C-2263 drum (right side)


Casting detail of replacement Centric C-2263 drum (right side)



Inner view of replacement Centric C-2263 drum (right side)

Problem: Unfortunately, for service replacement neither the original brake drums nor the Centric C-2263 are still available. So far, this reflects what was also written in other related threads.

So, I had to identify a new brake drum type. Comparing all characteristics and especially searching for drums fitting a 5x5 wheel bolt pattern and with nominal brake dimensions of 11” diameter and 2” show width, I found out that rear drums will fit from the rear axle of a 1974 Chevrolet C10 Pickup truck. Also, according to this post (Link: ClassicOldsmobile forum) such drums should fit. They have the additional advantage of being equipped with cooling fins.
I checked the available 11x2" drums for 1974 C10 pickup on Rockauto (since I can conveniently order from this company to my home in Germany/Europe) and ordered a set of drums. I personally selected the BendixPDR0254.

Solution: They fit and work really fine! See the attached pictures for reference:


Inner view of my new Bendix PDR0254


Bolt pattern & center hole comparison of the new Bendix PDR0254 vs. my old Centric C-2263. Fits nicely, just the center hole is ~0.4mm bigger on the new Bendix drum


Side view comparison of the new Bendix PDR0254 vs. my old Centric C-2263.


New Bendix PDR0254 mounted on axle. Fits nicely


Detail view


Top view of new Bendix PDR0254. Also the fit towards the backing plate looks good

Remarks:

CAUTION: Do NOT order parts like Centric since they have wrong (round) slots for the park brake lever. Check product images before ordering.
For the shoes, you should order parts which are listed to fit for the Olds 98 of 1967, e.g. Power Stop B462 or Bosch BS272. See following pics:


Correct trapezodial shape of park brake lever slot (top-most hole in the brake shoe)


"Wrong" round hole for park brake lever

CAUTION: Also here, the listed kit for 1966 Olds Starfire includes wrong springs and cannot be used!
Look for “1969 Oldsmobile 98 7.0l” hardware kit instead, e.g. Dynamic Friction P/N 37046005.

Use Dorman HW1544 (left), and Dorman HW1545 (right), or similar (these are the same P/N’s for front and rear brake).

Having solved the "obsolete rear brake components" topic, I hope this helps anybody interested. Now, I am very curious about the same topic for the front axle. There, we talk about 11x2.5" shoes and drum friction surface. Shoes are available, but no solution seems to exist for the front drums.

So my question to you is: Did anybody of you guys find a replacement front brake drum which works for the '66 Starfire?