I went to a local auto-electric outlet and bought the smallest ND they had on the basis that if it didn't fit it could be returned.
Never did get the model number, but it puts out some 48 amps compared to 28 for the original Lucas.
The mystery about the fit was the instal of the 2 L at the canted over angle that diminishes space for the alternator--it fits.
Also with the single wire set up the voltage regulator was no longer needed.
Two potential agents of unreliability have been removed.

Never did get the model number, but it puts out some 48 amps compared to 28 for the original Lucas.
The mystery about the fit was the instal of the 2 L at the canted over angle that diminishes space for the alternator--it fits.
Also with the single wire set up the voltage regulator was no longer needed.
Two potential agents of unreliability have been removed.