I'll address your "interceptor" and L32 questions. First, some of the engine specs can be found in the Chassis Service Manuals and Police info is in the SPECS brochures, all free of charge on Wild About Cars.
Olds didn't use the term "interceptor". Law enforcement vehicle were under the umbrella of "Police". The further breakdown came under "Police Apprehender", with 2 versions offered, the B01 City Cruiser and the B07 Highway Patrol versions. The L32 was the 390 HP version of the 455. The big difference from '68-'69 was that in '68 the L32 was was only available as a Police option, where in '69 it generally available. This became the W33 in '70. The Highway Patrol L32 was little more than a "Highway Patrol" air cleaner label and colder plugs. I can email you some pics if you'd like.