check out a past thread....
http://forum.73-87chevytrucks.com/smforum/index.php?topic=4772.15I have three pics in one reply on that thread.......the middle pic shows a vacuum advance.
Check your old distributor and see if you have a silver looking round thing attached to the distributor with a vacuum line going to it. If you do, it is a vacuum advance type distributor. When your vacuum pressure increases in the intake manifold, it pulls (sucks) the advance diaphram in the round cylinder, that in turn pulls the spring activated "guts" in your distributor...activates weights and springs and stuff to advance your timing which you will need under heavy acceleration.
ps. I regret not taking auto-shop in high school
I never took shop class--i took all college prep crap. Just learned by doing. I was tearing engines apart when i was 16 just to see how they worked. www.delbridge.net/vintage You can learn so much by just working on your engine yourself..it is very rewarding and your check book appreciates it too.