The 1940 Roadmaster had a shorter wheelbase, was lighter, and was less expensive than the previous year's model. The formal and fastback sedans were gone, but for the first time a 2-door coupe was available, which sold a respectable 3,991 units. Also new for this year, the coach-building firm of Brunn was asked to design several custom-bodied Buicks for the Series 70, 80 and 90. Only one Roadmaster example is known to have actually been produced in 1940, an open-front town car not surprisingly called the Townmaster. Overall sales more than tripled to 18,345. The styling changes for 1941 were modest, but the changes under the hood were major. The compression ratio was raised from 6.6:1 to 7.0:1, the "turbulator" pistons were redesigned, smaller spark plugs were substituted for the previous type and “Compound Carburetion” was introduced. Compound Carburetion was the forerunner of the modern four-barrel carburetor, and consisted of twin two-barrel carburetors. One unit operated all of the time, while the other operated only under hard acceleration. The new engine delivered 165 horsepower. With five more horsepower than a senior Packard, 15 more than any Cadillac, and 25 more than the largest Chryslers, it was the most powerful engine available that year on an American car. A new bodystyle for this year was a 2-door convertible, which sold 1,845 units. There was also one Brunn designed convertible produced, but priced at $3,500 actual orders for the vehicle failed to appear. Overall sales remained respectable at 15,372. The 1942 Roadmaster was longer, lower, wider, and roomier than before (a Harley Earl trademark), thanks in part to a longer wheelbase. There was also a new vertical-bar grille and "Airfoil" fenders that swept back all the way to the rear fenders, which in subsequent generations became the chromed "Sweepspear". Both features became a Buick icon exhibited in one way or another for years to come, and were influenced by the concept car called the Buick Y-Job. The 4-door phaeton was dropped and would never return. Coupes adopted the appealing Sedanet fastback style that had been the sensation of 1941 on the Century and Special. Effective at the beginning of 1942, new automobiles were available only to those in occupations deemed essential to the war effort.