Realising there weren’t 50 race drivers prepared to buy a GT40, Ford planned to dedicate part of the production run to fully equipped road cars. As a result of the extensive development programme carried out over 1964 and ’65, a finalised design was settled on and by summer 1965 production was underway. The aim was to produce two GT40’s a week until the end of the year, these cars using chassis numbers beginning with the prefix GT40P – the P identifying them as production cars. Eventually, FAV built 87 MkI’s, 31 of which were finished as road cars, the remaining 56 having been racers. The welded sheet steel semi monocoque chassis made by Abbey Panels of Coventry was unchanged although the MkI’s longer, smoother nose cowling required a different subframe assembly ahead of the main bulkhead. Once fitted with front and rear subframes, each unpainted chassis was sent to Harold Radford in London where the fibreglass doors and hinged front and rear bodywork were fitted. On returning from Radford’s, FAV assembled the suspension, steering, wiring, engine and gearbox before sending each GT40 back for final trimming of the interior, seats, glass and so on.

Displacement was 4736cc thanks to a bore and stroke of 101.6 x 72.9mm respectively, two versions having been available, one for street use, the other for competition. FAV equipped the competition versions with four twin choke Weber 48 IDA downdraught carbs. The valve covers and alternator were also modified and a bundle of snakes exhaust system fitted. With compression set at 10.0:1, the net result was a prodigious 380bhp at 6500rpm and 330lb ft of torque at 5500rpm. Perhaps most importantly of all, the prototypes achilles heel (Colotti’s unreliable four-speed transaxle) was replaced with a new five-speed DS25 all-synchromesh gearbox from ZF. Retaining the right-hand gearshift seen on the prototypes (all MkI GT40’s were right-hand drive too), the highly anticipated ZF unit worked in conjunction with a triple-plate Borg & Beck clutch. The finalised bodywork was modified with a flatter nose profile that required a different subframe assembly ahead of the main bulkhead (although a couple of early cars did feature the more slender front-end as used on 1965’s prototypes). This also permitted carrying a larger spare wheel and tyre as dictated by the new Group 4 regulations.

By contrast, GT40’s with the Weber set up boasted 335bhp and ran to 6250rpm, these cars also being fitted with larger air cleaners. Other niceties for road use included a less fierce clutch and more lavishly trimmed cockpit, the standard specification including nylon carpeting throughout, foam rubber soundproofing, a padded dash, heated screen, tinted safety glass for the doors and back window, door pockets, a door-mounted radio and improved heating system. Borrani wire wheels were fitted as standard and some cars also got Ford scripting on the nose. Customers could mix practically any combination of parts they wanted and consequently, some street GT40’s were fitted with competition engines, Plexiglas side and back windows and Halibrand wheels. As a result, two road-equipped GT40’s rarely tipped the scales at identical weights, most coming in around the 2050lb mark, only very slightly more than the 2000lb racer. In 335bhp trim, the GT40 was still an exceedingly quick motorcar, 0-60mph requiring a mere 5.3 seconds and 0-100 11.8, 164mph being possible flat out. By contrast, the competition variants could do 0-60 in 4.7 seconds, 0-100 in 8.8 and could top 185mph.

Nevertheless, countless wins continued to go the GT40’s way and in 1968, John Wyer’s Gulf-backed J.W. Automotive Engineering firm were unarguably the team to beat. That year, the regulations had been changed and a three-litre limit imposed on prototypes, this instantly killing off the epic Ford versus Ferrari battle that had raged over the previous couple of seasons. A five-litre engine limit for Group 4 sports cars gave the MkI a new lease of life though. Against the odds, GT40’s went on to take outright wins at Le Mans in 1968 and ‘69 against three-litre prototypes from Porsche and Alpine. By 1969 when the last road cars were rolling out of what was now John Wyer’s Slough factory (Ford having handed the reigns over at the end of 1967), MkI GT40 racecars were using Gurney-Weslake heads and stronger bottom ends for over 400bhp. JW’s super lightweight Gulf-backed cars had even more tricks up their sleeves with stroked five-litre engines, dry sump lubrication and flat tappet camshafts for around 415bhp. In addition to the 87 official MKI’s manufactured, two cars were built up by Alan Mann Racing whilst a further seven were later completed as post-production examples.