Bob, if you can find the Type 3 drums, well done. I looked everywhere. They're out there if you can find them in a paddock somewhere by chance and someone will sell them to you. Most people want in excess of $200 for a set that need a lot of work. After alot of searching I ended up using my original drums with 68 beetle backing plates and brake hardware. You can only do this on the buses up to 62-63. If you're bus has a big nut box in it, try to get the type 3 gear (or the earlier bus drums), if not, the originals fit with a bit of machining. The machining for mine cost $130 and that was including machining of the braking surface. Follow this link and all is explained.............
http://www.bus-boys.com/instruct-swing-pg1.htm
Ross.