To convert from a normal distributor-based system to a mapped system is not as difficult as you might think.  In addition to the EMS/mapped ignition unit you will need a throttle potentiometer to measure throttle angle (and therefore load) which needs to be attached to your throttle spindle, and a distributor with no advance mechanism, in place of your existing distributor.  Usually most of the existing ignition system - coil, leads, plugs, distributor cap and rotor arm can be retained.

As an alternative to replacing the distributor the existing one can have the advance mechanism locked to ensure that it gives a constant signal to the EMS.  This can be done by drilling through the weights and baseplate and inserting a self-tapper or by brazing/’MIG’ing the advance mechanism solid.

The EMS will require an electronic signal from the distributor so a points-based distributor will not do.  Most post-1980 engines have electronic ignition so if your engine doesn’t have an electronic distributor it is usually possible to find a later distributor for your engine, that has a magnetic reluctor or Hall effect trigger.  Some later versions of your engine may well have a factory-fitted EMS which uses a Hall effect or reluctor-triggered distributor that may also not have an advance mechanism.  If so this is ideal.  If you cannot find a suitable replacement, then a Lumenition eye fitted in place of the points will do the trick.

The EMS will require some fairly straightforward wiring in and obviously will require a mapping session on a rolling road.  Most EMS suppliers have example maps available which are ‘safe’ and will get you up and running for your trip to the rolling road.   If you don't have a map to start with then the existing curve from your mechanical distributor can be plotted using a timing light and some patience, and then programmed into the EMS.  Adjustments can be made for part throttle, starting and idle and this should get you going.