Ch4b

(CH)rysler (4 B)arrel <RB>, as opposed to the (D)odge (P)lymouth (4 B)arrel <B> and then there is the (D)odge (4 B)arrel <first 273>, (L)ittle (D)odge (4 B)arrel <LA> and also the LD340 with the larger ports. The Little is not accurate but helps remembering it. There is also a D64 early 273 4bbl.