You will need to buy a dwell meter if you are going to retain your points.
Or you can convert your existing (and probably well worn but numbers matching factory points distributor) over to an HEI with a module from Pertronix. Here is the instruction sheet to convert it over to let you know what you are getting into:
The advantages of HEI are no more points bounce (which is why high performance cars had dual point distributors) due to the fact that there are no points involved. there is also no more constantly adjusting your dwell all the time as the points burned under normal use. And the thing most cite as the best result, easier starts as the ignition is internally regulated to four volts so there isn't a voltage drop to worry about like there is with points in your ignition.
Even with an HEI ignition you will still need a tachometer that you can read under the hood and a BIG vacuum gauge that you can also read. A bigger gauge moves the analog markings further out from the central pivot so it is easier to read the actual amount of vacuum.
Here is a vacuum gauge made to adjust mechanical fuel injection with individual runners or as pictured for tuning Webber carbs. It allows you to tune each stack to get the same vacuum reading so you don't have to put corks in a nice doctor's Jag because you don't know how to tune multiple carburetors (something I grew up with back before big four barrels where invented).
And finally a timing light. Here you may want to think ahead because a awful lot of timing lights with a dial back feature do not work with a capacitive discharge ignition box. You can buy the expensive timing light from MSD that works with their boxes or a cheap one from Sears that also works where few others do.
Which brings up two more questions. First why bother with a dial back timing light when you can put on a piece of timing tape? That is because the factory timing marks are limited to twelve to fourteen degrees of advance when your motor is actually going to want about thirty four to thirty six degrees of advance total (vacuum and mechanical combined). With a dial back you turn the dial to what you want the total to be and it will flash a the TDC mark. With a standard timing light and tape it will work just as well until the tape falls off.
Second why even consider a capacitive discharge ignition system over the factory inductive ignition? If you thought it was easier to crank up with an HEI you will love a CD ignition system.
MSD stands for Multiple Spark Discharge. That is the spark plug fires up to four times when cranking to light off a lean mixture (MSD was introduced in the seventies when the factory was going overboard trying to meet emission laws that hadn't even been written yet). As the RPM increases the number of pulses drops off so that by 3,000 to 3,200 RPM it is only firing once. It is these multiple spark firings that confuses a digital dial back timing light.
One other feature that CD has over HEI is that the HEI is transistorized. So like all transistorized devices it is susceptible to heat. As your RPM increases the HEI module gets hotter and hotter. Generally above 5,600 RPM a factory HEI is missing about as frequently as it is firing. In later model computer controlled HEI distributors they used this "feature" as a rev limiter in BBC applications. MSD and many aftermarket HEI distributors have special modules with a built in heat sink that works with the billet aluminum body of the distributor to shed heat more quickly. The MSD billet Street distributor (includes a vacuum module) is good to 6,800 RPM before heat becomes a problem.
With a CD the ignition isn't dependent upon an HEI module to amplify the weak Hall Effect induced current. The magnetic pulse is just used to discharge the fully charged capacitors (that are charged from the battery, not from the magnetic field in the coil collapsing). The coil is now used only as a transformer, instead of a magnetic flux capacitor. So a MSD 6AL ignition box makes for a smooth start, and delivers a high energy spark to your ignition.