A decent parts house would other wise, Summit, Jegs, Speedway, that auction site. There are a few manufactures, but the kits are all basically the same with minor variations. What you should look for are 3 pr of springs, (light, medium, and heavy), a pair of weights, 2 pr of bushings (this is not always the case). The bushings are for the weights and the pivot posts they ride on. The weights are useable but not as well made as OEM. There is also a center plate.
He's a couple of links;
Disassembling distributor.
http://www.rustpuppy.org/ignition2/Ignition%202b.htmRe-curving. this link isn't the best for curving a distributor.
http://www.rustpuppy.org/ignition2/Ignition%202b.htmthis link is better
http://www.442.com/oldsfaq/ofign.htm#IGN%20TuningLarry