1. Distributor Type 

45D with Vacuum , chose this for general road use 

43D Non Vacuum , generally chosen for fast road use. Vacuum is only generally created at tick over and cruising and not considered necessary for fast road use 

2. Trigger Type 

Points : Traditional points and condenser type distributor 

Electronic : Distributor has no points or condenser and is fitted with the   Module with adaptive dwell control . 

3. Cap type 

Top Entry cap

Side Entry Cap 

4. Drive type

Offset keyway: Most common type of drive . Fitted to all cars such as BMC , MG , Triumph , Reliant 4 cyl , Land Rover, Morris,  Lotus ( not twincam ) 

Ford Drive:  As fitted to all cars with the Ford Pre-cross flow , Cross-flow and Twin cam engine . Also known as Kent and OHV engine .