The brake drums you need are super RARE to find in GM NOS .
This photo shows the last two that I've seen on ebay.
photo@photobucket
http://i669.photobucket.com/albums/...k_Front_Brake_Drums_NOS__zps4nsu0f08.jpgThe Rear drums are also super RARE .
My friend who has a 1950 3600 bought these two GM NOS rear brake drums.
One on ebay back in 2006 for $50.00
&
another from W.D. Foster down in Texas for $150.00.
photo@photobucket
http://i669.photobucket.com/albums/...Rear_Brake_Drums_GM_NOS__zpshjtlekvp.jpgOnce in a blue moon someone will re-finish a used brake drum that still
has not reached the " NO GO " limit and offer it up for sale.
These rear brake drums were on ebay a few years ago.
photo@photobucket
http://i669.photobucket.com/albums/..._Brake_Drums_GM__609807__zpstofxzn0k.jpg