Yet, there are external changes which detract from authenticity if blocks are swapped.Some of the more significant improvements to the basic straight-8 design incorporated during the 23-year period follow.- Compound carburetion introduced on all Super, Century, and Roadmaster models as standard equipment and available as an option on all Specials.This year 10 mm spark plugs were also used and the forerunner of a PVC (positive crankcase ventilation) system was pioneered which vented the oil vapors to the carburetor through a small tube from the top of the valve cover to the air cleaner.Over time, these effects can disrupt the smooth movement of the valve on its shaft and the thermostatic spring can lose its temper.
The small engine was increased to 248 CI in 1937 and to 263 CI in 1950.
- A larger, more reliable oil pump was introduced along with an improved radiator and a 7 psi radiator cap.
Buick also begin using a "assembly balancing" technique which tested each engine complete with clutch to eliminate unwarranted vibrations before installation.
A downdraft carburetor was first applied on the small engines replacing the updraft models which were used from 1931.
- Aluminum rocker arm shaft brackets employed to provide a quieter valve train.