Gordon,
If you can find an old inductive timing light, your good. (the kind with the metal housing / body - SUN, Craftsman, MAC, Matco, Snap-On, etc). You can find them on Ebay or swap meets for ~$20-30. (Which reminds me, this Sunday is a 'Super Sunday' in Indy... )
The newer style lights have issues.
I have an old SUN Test Equipment 7501 light that I use. It looks brand new and is several years my senior..
Here is a link to one on EBay right now. $20 to your door!
http://cgi.ebay.com/ebaymotors/Sun-Indu ... veQ5fTools