Buick 455 police pack alternator?


Hi everyone

In 1974 Buick shop manual for A bodies we have 37 AMP (1100947) as Alternator standard, for air con models 42AMP (1100926), that both are 10SI models, but we have also police pack option alternator that is 80 AMP (1101018) that I guess this is a 27SI model alternator, If I`m wrong please let me know, but If it is a 27SI model how they install this on 455 BBB engines? It needs a different holder and mounting parts?
Yes, the Delco-Remy site confirms the 1101018 is a type 27SI:

Here is a drawing from the Master Parts Book showing the mounting of the '71-72 version of the 80 amp. It should be very close to the setup on the '74. The bracket, brace, and pulley part nos are different for the 80 amp Delcotron. The 80 amp units show up more and more in the parts lists of Buick and other GM brands as electrical loads continued to rise in the late '70s and early '80s.