The inlet valves are larger than those on the 12/70, and the triplex chain drive has the addition of an automatic tensioner.

The exhaust system was extensively revised, and the direction of flow of cooling water around the engine was substantially changed.

[5] The body is mounted on an updated pre-war Alvis 12/70 chassis that is wider and longer, but retains rigid-axle leaf spring suspension.

Hypoid bevel final drive was fitted for the first time, greatly reducing the height of the transmission tunnel.

[1] Autocar reported that the new car had the typical Alvis refined, sure-footed, and lively performance.