By the mid 70s the GTO was just a option on the Lemans chassis , the engine and transmission choices were identical for both cars, only the body was different in that the GTO had a specific nose, hood and front fenders, that were only used on the GTO and GT-37 models..
the GTO offered the 400 and 455 engines while the Lemans and GT-37s were offered with any Pontiac engine available for the chassis..
the engines were also now rated at SAE Horsepower ratings not Gross HP as pre 71 engines were..
the GTO was continued for 73 in the colinade chassis Lemans and in 74 sunk to a lowly
Nova based Ventura chassis with a 350 ci engine as it's only option ..
it was then summarily put to rest until the 2004 model Holdon based GTOs came out with the LS series engines ...