I just noticed that the drums on my car has a different number of circled "plates". Why? What are they for?
Of course I didn't paid attention where each drums were going...

 

Just guessing but maybe they're balancing weights like what you'd find on wheels?

 

^99% sure they're weights, shouldn't matter what order you put them back on. Should all be balanced either way (like a tire rotation)

 

I also had confirmation from another source that they are weights. I have 2 rears and 1 front (2nd front still on the car). I have 2 with one casting number and the other one with a different number. Are they the same front and rear?
I have not removed the wheel to check numùber on the 4th one yet...

 

Should be the same I think and probably the same on quite a few other Chevys over a number of different years.
That said I'd want to do a disc brake upgrade on the front,they were an option on 1st gen Camaros.

 

They looked quite the same and I was just wondering about those markings.
Disc brakes option is not for now for me. Maybe later...