While similar to the earlier V-8-powered TVR, the Griffith 400 was an improved version of the 200. It featured a 289 cid Ford V-8 mated to a Borg Warner 4-speed manual and a new Salisbury differential. As with its predecessor, the Griffith 400 was clothed with the Blackpool-built fiberglass coupe bodywork from the TVR Grantura Mk. IV, along with TVR rack and pinion steering as well as independent suspension front and rear. Brakes were power-assisted front discs and rear drums. Final assembly for the car was done in the U.S.

The Griffith 400 was introduced in late 1964 and, unlike the first Griffith, was not available with the Ford “200” engine. Improvements included a new 2.73.1 rear axle ratio, redesigned rear suspension and a larger radiator that had two electric fans for the tightly packed engine bay. The 400 also benefited from improved construction. A chrome strut attached the roof to the fascia to prevent the body integrity problems of the 200. The top speed was 155 mph with 0-60 mph achievable in 4.6 seconds, although a racing version as tested by John Bolster for Autosport in October 1965 could achieve 163 mph. Bolster found the Griffith to be “a sheer delight,” although some would just as quickly describe the lightning-quick short wheelbase Griffith as terrifying.

The dock strike on the East Coast during 1964 and 1965 severely affected the importation of body shells from Great Britain and essentially brought Griffith 400 production to a halt after only 59 units. While the Griffith 400 boasted many improvements over the Griffith 200, there were complaints of inadequate braking. Other problems for owners today include deterioration of the fiberglass body and corrosion of the chassis. And despite the new radiator, the Ford 289 is crammed into the Griffith and may still be prone to overheating. Even so, performance is blistering even in the company of the better known Cobras, Ferraris, Corvettes and Jags of the 1960s.