From Wikipedia:
In 1961 a new 2.6-litre (2,553 cc (155.8 cu in)) straight-six ‘Ruddspeed’ option was available, adapted by Ken Rudd from the unit used in the Ford Zephyr. It used three Weber or SU carburettors and either a ‘Mays’ or an iron cast head. This setup boosted the car’s performance further, with some versions tuned to 170 bhp (127 kW), providing a top speed of 130 mph (209 km/h) and 0–60 mph (0–100 km/h) in 8.1 seconds. However, it was not long before Carroll Shelby drew AC’s attention to the Cobra, so only 37 of the 2.6 models were made. These Ford engined models had a smaller grille which was carried over to the Cobra.
AC came back to the market after the Second World War with the 2-Litre range of cars in 1947, but it was with the Ace sports car of 1953 that the company really made its reputation in the post war years. Casting around for a replacement for the ageing 2-Litre, AC took up a design by John Tojeiro that used a light ladder type tubular frame, all independent transverse leaf spring suspension, and an open two seater alloy body made using English wheeling machines, possibly inspired by the Ferrari Barchetta of the day.
Photos from Classic Driver website: https://www.classicdriver.com/en/car/ac/ace/1961/703263?utm_medium=email&utm_campaign=Classic%20Driver%20Daily%203342019&utm_content=Classic%20Driver%20Daily%203342019+CID_08b403976196024a8806d6851989b77c&utm_source=newsletter