In general terms,

F40 Special Suspension consisted of h.d springs & h.d. shocks.

F41 Special Purpose Suspension consisted of standard springs (for ride & compliance), h.d. shocks plus front & rear stabilizers matched up as a team.

BTW taxis & police cars usually came with Z04 h.d. Chassis Equipment which included F40 suspension, front stabilizer added to 6-cylinder Biscayne & Bel Air sedans (when normally they were omitted from those applications) and a h.d. rear axle (12-bolt). Other stuff included were h.d. clutch on 6's, V01 h.d. radiator & a K79 alternator.