Lotus only built one Formula 5000 design, a series of cars starting with a prototype Lotus 68 at the end of 1969, and continuing with a series of production Lotus 70s in 1970, and finally a few modified Lotus 70Bs in 1971.
As well as the purpose-built cars, the Lotus 42 Indy car was converted for Formula 5000 for the factory, and both ex-Formula 1 Lotus 43s were converted to F5000 by Ken Nichols for Robs Lamplough in the UK in 1968. Also, two earlier ex-Formula 1 Lotus 24s ran in occasional British F5000 events (including Chris Summers' chassis 942 shown here) as did an ancient Lotus 18 (Mike Panico's chassis 910, also coincidentally ex-Chris Summers). One of the Lotus 40 sports cars was converted by Chas Beattie to be the 'Conchord' F5000.
In the US series, both Crocky Peterson and Frank Eggers raced ex-Indy Lotus 38s. The 'Unser-Lotus-Chev', said to be built by Bobby Unser on the remains of Lotus 18 371, was run by Gene Willbanks in US FA in 1968. Another Lotus 24 was raced by Chuck Trowbridge with a 289 Ford V8 in 1967 and 1968, this one thought to be 941 but said in one 1968 report to be the car Al Unser used to beat Bobby Unser in the 1965 Pike's Peak hill climb.
|Lotus 42B||1967||2||Built for Indy but one car converted by Lotus to FA specification. Monocoque chassis. Original Indy dimensions: Wheelbase 8'; maximum track 5'; length 13' 6"; dry weight 1350lbs. FULL CAR-BY-CAR LIST AVAILABLE|
|Lotus 68||1969||1||Built late 1969 as a prototype 'wedge' Formula A/5000. Raced at Sebring December 1969 by Mario Andretti. Later modified to Lotus 70 specification. Engine: 4945cc Ford Boss V8. FULL CAR-BY-CAR LIST AVAILABLE|
|Lotus 70||1970||5 (plus converted 68)||Production version of the 68. Monocoque chassis. Wheelbase 8' 2"; maximum track 5' 1"; length 12' 8"; weight 1300lbs. FULL CAR-BY-CAR LIST AVAILABLE|
|Lotus 70B||1971||3||Modified version of the 70 built in 1971. Only was was completed; the other two being sold in kit form. FULL CAR-BY-CAR LIST AVAILABLE|
Also in the US series, Vernon Shields appeared in a Lotus 35 with a Ford 289 V8 built for him by Marvin MacAfee. This car appeared rarely. One outstanding mystery is the USAC Lotus that Gil Roth (Wexford, Penn) entered and advertised in 1970 but never raced.
All and any help would be gratefully received. Please e-mail Allen at email@example.com if you can add anything.
Sources include: The Story of Lotus 1961-1971 (Doug Nye), Competition Press & Autoweek (8 Jun 1968 p6), and Team Lotus (Andrew Ferguson).