▁but ▁where ▁Fl x ible ▁had ▁an ▁advantage , ▁was ▁the ▁market ▁for ▁ ▁long ▁bus es ▁equ ipped ▁with ▁ 8 - cy l inder ▁dies el ▁engines . ▁In ▁ 1 9 6 6 ▁G M ▁began ▁offering ▁its ▁Detroit ▁Dies el ▁ 8 V - 7 1 ▁ 8 - cy l inder ▁dies el ▁engine ▁on ▁its ▁ ▁New ▁Look ▁trans it ▁bus es ; ▁however ▁G M ▁would ▁not ▁equip ▁its ▁ ▁models ▁with ▁anything ▁larger ▁than ▁the ▁ 6 V - 7 1 ▁ 6 - cy l inder ▁dies el ▁engine . ▁In ▁response ▁to ▁the ▁desire ▁by ▁some ▁trans it ▁ag encies ▁for ▁a ▁shorter ▁bus ▁with ▁a ▁larger ▁engine ▁( main ly ▁for ▁h illy ▁routes , ▁fre ew ay ▁driving , ▁or ▁to ▁provide ▁extra ▁power ▁for ▁air ▁condition ing ▁equ ipped ▁bus es ), ▁Fl x ible ▁offered ▁its ▁ ▁New ▁Look ▁with ▁the ▁Detroit ▁Dies el ▁ 8 V - 7 1 , ▁the ▁C umm ins ▁ 1 6 5 - 2 8 5 , ▁and ▁the ▁C umm ins ▁ 9 0 3 ▁ 8 - cy l inder ▁dies el ▁engines . ▁ ▁Model ▁design ations ▁Several ▁different ▁variations ▁of ▁model ▁design ations ▁were ▁used ▁for ▁Fl x ible ▁New ▁Look ▁bus es , ▁with ▁changes ▁being ▁made ▁over ▁time ▁and ▁between ▁the ▁various ▁manufact uring ▁locations . ▁The ▁letters ▁and ▁numbers ▁gave ▁a ▁basic ▁description ▁of ▁the ▁type ▁of ▁bus ▁as ▁follows : ▁ ▁Two ▁typical ▁bus