From a ClassicDriver.com online article:

“Originally designed as both a road and racing car, little compromise was made for comfort and practicality. With a light body and a peppy 2½ litre Riley engine, the Healey Silverstone performed well; even the headlights were brought inside behind the grille to make it more aerodynamic. It had a very limited run; just 105 produced making correct examples extremely desirable. 

…Donald Healey himself raced one, winning the 1949 Alpine Rally. A Healey Silverstone also won Belgium’s Liège-Rome-Liège Rally, the Isle of Man Manx Cup, various races at Goodwood and other national events.

Due to the limited production run, cars with important period competition history are desirable and so when a previously undiscovered chassis turns up, correct identification is key.

To read more: https://www.classicdriver.com/en/car/healey/silverstone/1949/712691?utm_medium=email&utm_campaign=Classic%20Driver%20Daily%203252019&utm_content=Classic%20Driver%20Daily%203252019+CID_45cd83d4933f01b9587a4a72c19b3141&utm_source=newsletter