Differences between 45DM4 and 47DM4?

[Brian Furgalus <triumph.tr7@usa.net>]

To All:

Are there any major differences between the 45DM4 and the 47DM4 Lucas
distributors?  I'm contemplating fitting an Allison ignition system to my '81
7, to replace the original ageing AC-Delco coil/amplifier assembly that's
being used with a new(ish) 47DM4 Distributor.  Allison and Crane only list
units for the 45- series  units.  Will these work with the 47- series units? 

Thanks,
Brian

1981 TR7 DHC, coming along now!