The anaerobic Permatex at left could be my choice for engine case halves, provided it is a low strength type. For simpler covers any other types should do , when not much load gets transmitted by the seal from crank or gearbox components forces. In these places silicon or Hylomar is allright but not my choice on crankcase halves when a lot of forces from crank plus Vincent suspension/frame functions require a dead-solid unit .
Most times I won´t take silicon for gaskets in an engine, how do you remove remains of silicon before next assembling ?? Anaerobic seals can be softened with paint stripper and cleaned with plastic scraper, Hylomar with acetone, but silicon - messy.
Vic