My first step in trying to "improve" my car was to put the Pertronix unit in (Gary's dist. wasn't available at the time). It made a noticeable difference and I was quite happy with it. However, my reasearch (fancy term for reading too much) led me to believe I needed a larger spark gap for optimum milage/power.
So, I went to a Jacobs unit triggered by the Pertronix with about a .055" gap. Again a noticeable improvement, and I was happy with that for several years. More "research" led me to the EDIS, but that is another topic.
I think the Pertronix unit is a good first step. There is now a Pertronix II which, I think, allows for a 12V coil, but I don't know if it is available for the roadster.
If I were to use a dizzy, I would go right to the newer electronic dizzy.
For the extra $100-$150 you get:
1. A solid dizzy with good bearings that will probably outlast your engine
2. A larger cap, which puts more distance between posts and lessens the chance of "crossfire"
3. A 12V coil and 0.043" spark gap to improve both power and milage
4. An excellent advance curve, set up for the roadtser (newer, better mechanisms for that curve?)
5. Parts availability for years to come.
Did I leave anything out?
my $0.02