OLDSMOBILE — SIXTH SERIES — MODEL 37A & B — SIX: For this model year Oldsmobile designated its open cars of six cylinder design as 37-A's, while the closed cars were 37-B's. The cars shared mechanical and chassis components. The six cylinder models continued as the most popular Oldsmobiles in 1920. The series 37 cars were essentially carryover models from 1919.