The Hupmobile K-321 was a series of automobile built on a 121 inch wheelbase which was a few inches longer than that of the B-316 (the K-321's predessor). The L-head 228 cubic inch engine had the same bore and stroke as the B-316 but now had an additional 90 horsepower. This was because of increased compression ratio.
Four models were available, a four door seden, coupe with rumble seats, a five passenger Victoria coup and last but not least the convertible. Prices ranged from $995 (sedan and rumble seat) to $1,095 (convertible). Luckily, a cheaper series was added later. There were some design changes in 1933. The grille now had a slope and the hoods had grown longer. Hood vent doors were extended to the smaller eight and the K-321. 4,600 were made and it was proved to be one of the most popular cars from 1933.