I know 70 and other years had both aluminum and iron front brake drums. What was the determining factor if a 70 received aluminum drums or iron drums ? Option code ?
I don't know the option code. Most of the big block cars I have seen have the aluminum drums while the small blocks has steel drums. Maybe it was a part of the big block standard equipment.
OK, After digging thru my info and various Factory info (for 1970) I discovered the following info. 1. There was no (zero) option codes available for either iron or aluminum front drums. There were options for power front drums or disc brakes only. That means the type of front drums that came on these models was "Standard" for that particular model with zero options for upgrades. You could opt for power ony with drums, and if you bought discs, then power was standard. 2. I did not find anything showing what was "standard equipment" for a 70 GS 350 or GS 455/Stage 1. I do have some more factory info to look thru but didn't get to it yet. 3. I personally had (2) 1970 Stage 1 4-speed cars with original date coded front drums. One was an early car with manual drums, while the other was a late car with Power drums. Both cars came with the larger Aluminum drums and the bigger wheel cylinders. Now I know the 70 Stage 1 cars came with them "stock", but do not know if the 455 cars had them as well. We also had a 70 GS 350 with correctly dated cast iron front drums, so that should answer that. If I get time I will try to dig further, but....................................................... Duane PS. Years ago I wanted to figure out how each specific 72 GSX was optioned, and I remember it being hard to figure out how the 1972 "base" cars came. I believe I had to determine what each option was and then take it "off" the list. By doing that the result was how a base car was built. Someone might need to spend the time and do this for the 1970 cars to figure this out.
My understanding is that all 1968-1969 and 1970 Big Block GS cars with either manual drum front brakes or Power front drum brakes came standard with these special finned Aluminum brake drums. Small block GS cars received in same applications and model years received cast iron drums.
This is a scan from a 1970 Salesman's Price Directory showing standard equipment for GS and GS455 models. Aluminum front drums are indicated as standard on the GS455. Power assist (option code C7) is an option on both models, with no mention of change of drum material.
Interesting thread.......... My first car, a '70 GS 350, had power aluminum drums. Built in Kansas. Could this have been a plant thing?
