The Frua is built on an AC Cobra 427 Mark III chassis extended by 6 inches (150 mm).

Chassis construction was similar to most Italian supercars of that era, with square and rectangular tubing connecting the steel body to the frame.

Though the 4-inch (100 mm) tubular chassis allowed both coupé and convertible versions to be rigid, the design was intricate and prone to rust.

John Mclellan wrote in his book "Classic ACs, Auto Carrier to Cobra" that Derek Hurlock once said to journalist Mike Tailor: "I like the 428 because it fits my image of a true GT Car".

This one AC that joined that select company of very fast, very luxurious touring automobiles which moved effortlessly from current model to collector's piece".