Engine Identification Number

I was wondering if someone could help me I checked my engine ID number at this link [http://www.mgcars.org.uk/namgbr/identify.htm] and could not find my engine number. The engine number is 18V672ZL12167. According to the website:

18V = 1800 Vertical (inline)

672Z = This is the number I could not find

L = Low compression

12167 = Serial Number/

I would be greatful if someone could tell me what 672Z means.

672 is a North American spec. engine without overdrive and with AUD 550 HIF4 carburettors for years 73 & 74 .
Z is for twin carburettors and emission control North American only.

Thank you!