In Reply to: 74 "02" distributor question posted by Glen on September 09, 1999 at 10:19:58:
I believe the '008 was original Tii and the '002 is still manufacturered and was originally for VW. Set timing to maximum it will take without pinging. The standard method is to rev the engine up to about 3500RPMs and advance until the engine starts missing a bit and then back off a little. Then go road testing up a steep hill, in 5th gear on the the lowest octane gas you plan to run, and the hottest day of the year. If it pings, keep retarding the timing until it doesn't. Severe pinging will kill the engine, so be careful.
I have seen enough debate and anecdotal information on the subject to say that there is only one way to find out for sure on any particular car: get both distributers and experiment. I'm doubting that there will be any more than a handful of foot*lbs of difference at any given RPM and load between the vac and non-vac units, especially on a stock engine, but you don't know until you try.