as a credit option for the standard L37 301. The main upgrade for the engine was the ESC, (Electronic Spark Control) which provided slightly more power at with for the 1980–1981 model years. The 1981 rendition of this engine was officially called the 301-EC [EC standing for Electronic Controls] in the 1981 GM factory service manual, removing the need for a W72 option separately as it was now the standard motor, similar to how all W72 engines in 1979 were coded L78. One of the key modifications over the standard 301 4-barrel was the 301 Turbo block. The 301T block was significantly more durable than the standard 301 block and received a thicker bottom end. This included the ESC (Electronic Spark Control) distributor and controller borrowed from the 301 Turbo, which allowed for higher timing without the penalty of engine damaging pinging or preignition. A larger ram air flex duct to the air cleaner from the left-hand fender, specific carburettor calibration for the Rochester Quadrajet, a "T/A 4.9" callout on the shaker, 60 psi oil pump, and cam similar in grind to the 400 from the 1978–1979 model year were also included. Unfortunately, there were no improvements in the casting number "01" small-valve high-velocity heads, which would have yielded greater improvements in power. Additionally, the 301 W72 never received the option to come equipped with a manual transmission like the standard 301 received in 1979, and disappointingly, production for all Pontiac V8's ended soon after as GM sought to "corporatize" engine production. Ram Air The beginnings of Pontiac's iconic Ram Air dynasty began during the 1965 model year. The GTO's new hood scoop design, with the inlets centrally located and mounted above the carburetor, provided the opportunity for experimentation. Royal Pontiac developed the prototype of the package on their 1965 GTO drag car and Pontiac picked up the idea and in August 1965 Pontiac offered the new Fresh Air package to dealers consisting of the parts and instructions needed to make the hood scoop functional, including the metal tub to mount to the carburetors and rubber gasket to seal it to the underside of the hood. The Fresh Air package continued into the 1966 model year. Around January 1966 Pontiac took the next step and began offering as a factory option the XS-code engine. It included a new camshaft with duration increased from 288/302 (No. 068) to 301/313 (No. 744)