CO HI: Buick's history during the late 1930's, early '40's, was quite interesting. They did have two basic engine blocks that were used in at least two different body sizes. In about the mid 30's they introduced the Roadmaster (which we irreverently called the Road ******* or the Road Smasher) That car used the "C" body which GM reserved for Cadillacs, large Buicks and large Oldsmobiles (98's) The "B" body, which was shared with Chevy, Pontiac, smaller Olds and smaller Buicks, became the basis for the Buick Special (and one more very special car), also the Olds 88 and 76, etc. That larger "C" body was also used for the Buick Super, which had the smaller engine.
Since about 1932, all Buicks were straight eights but one was smaller, I don't recall the exact engine size but the displacement was around 248 cu in. The larger block, which was actually physically longer, was about 320 cu in. Of course the small block was the power not only for the Special, but also the Super in the larger, heavier body. The big block became the power, not only for the Roadmaster but also for Buick's "Hot Rod", the Century, so named because it was the first production car designed to exceed 100 mph. This model used the large 320 cu in engine in the smaller "B" body with an extended front clip to fit the longer motor.
Over the years, those engines were improved and HP was cranked up until in 1941, both the Roadmaster and the Century were equipped with dual carburetors and rated at 160HP, more than even Cadillac's flat head V-8. For their day, those cars were really quick, both in acceleration but also top speed. But actually the engineers really missed an opportunity to improve performance as well as economy. (Probably not too important in a day when gas was about $ .15 cents a gallon) The carburetors were set up to operate progressively, that is, the front carb. fed the gas mixture for 90% of the time, the rear was set up to feed only when you floored the gas pedal. So for most of the time, the fuel mixture came only from the front carb which was a long way from the last cylinder. Not a very efficient layout. If the carbs had operated in tandem, both working at the same time, the efficiency of the whole system would have been much better.
!938 was when Buick introduced it's "torque tube" drive shaft with coil rear springs, an improvement over the flat, leaf springs from earlier. To me, the most desirable Buick to own, as a collector's car, would be a 1938 Century Convertible with side mount spare tires. How classy could you get??? And you could beat darn near anything of it's time, short of a Duesenberg or a supercharged Cord.
Paul Fischer