[2] Colin Chapman issued a brief that listed the features to be required in a new engine, including 'high efficiency, flexibility, torque and smoothness which was suitable for hand assembly'.

The block would be angled at 45° from vertical to permit a lower bonnet and simplify development of a 4-litre V8 version for future use in Indianapolis racing.

With valve train issues causing a DNF Bill Blydenstein took over the engine builds and fitted the Lotus 907 head to the DTV Group 2 rally Vauxhall Magnum Coupes.

[7][8] A rule change in 1978 by FISA made the Lotus-head cars ineligible to compete and Vauxhall switched to their own DOHC head.

The Vauxhall blocks developed cracks around their main bearing bolt bosses, so a special batch were made with thicker castings.

[4] The 905 engine experienced wear on the connecting rod against the crankshaft webs, which was solved by boring rather than honing the bushing on the small end of the con-rod so that it held more oil.

[2] One change was to split the case along the crankshaft centre-line and incorporate a separate one-piece bearing cap and engine skirt girdle.

This change eliminated the need to machine deep main bearing saddles and restored some stiffness to the block assembly.

Another issue was that the alloy blocks used wet liners which were poorly supported in the initial design and this caused a high rate of cylinder head joint failures.

Transmission vibration thought to be caused by insufficient beam stiffness in the engine/transmission assembly was addressed by adding two lugs to the lower edge of the crankcase.

[2] An updated Jensen-Healey Mk2 was introduced late in 1973 with a revised engine having a redesigned crankcase, but by this time the car had already acquired a reputation for poor reliability and sales never reached expected levels.

In 1977, Desmond "Des" O'Dell, Director of Motorsport for Chrysler UK, approached Chapman about having Lotus supply a 900 series engine for a special project.

Driver Henri Toivonen won the RAC Rally in 1980, and teammates Guy Frequelin and Russel Brookes were third and fourth.

Only two prototypes were built before the project was cancelled due to PSA favouring development of the four-wheel drive Peugeot 205 Turbo 16.

This hybrid engine used a Vauxhall Slant-4 iron block and the Lotus DOHC aluminium cylinder head with Tecalemit-Jackson fuel injection.

The air intake angle was almost vertical with larger ports than the Lotus 907 head, with maximum valve sizes of 37mm inlet and 35mm exhaust.

The final development version LV265 increased power by moving the water cooling to the exhaust side of the head, keeping the inlet temperatures lower and giving 265 bhp.

Lotus found the block cracked racing so reinforced the 3 centre main bearings, this modification was used on all the DTV engines.

[15] Blydenstein also fitted the LV240 to a race Vauxhall Viva, winning the 1971 & 1972 Irish Saloon Car Championship, driven by Des Donnelly.

Applications:[citation needed] The type 906 engine had a sand-cast version of Lotus' new aluminium block and Tecalemit-Jackson mechanical fuel injection.

It was used in a Formula 2 open-wheeled car that had the same "Type 74" designation as the Lotus Europa Twin-Cam and was commonly called the `Texaco Star'.

[19][20] The Formula 3 engines in the two Type 74 Texaco Stars were prepared by Novamotor in Italy and were rated at 275 hp (205 kW).

[2]: 39–40  The 907 (and the subsequent 912) were offered in several levels of tune, called `specs', that ranged from 1 to 10 with different compression ratios and power outputs.

[21] Even though they produced respectable power for their size and era, early 907s earned the nickname "the torqueless wonder" for their lack of bottom-end torque.

[24] While this 900 variant was mentioned in Rudd's original paper it only appeared in the Lotus Etna concept car that debuted at the Birmingham Motorshow of 1984.

The compression ratio was raised to 10.9:1, and the engine also received revised ports, new camshafts, new Mahle pistons and alloy cylinder liners with a Nikasil coating.

[28] New camshafts that increased both lift and duration were added, as were sodium-filled exhaust valves and larger water passages in the cylinder head.

[32] In markets with stringent emissions requirements the 910 became the first 900 series engine to use fuel injection with the addition of a Bosch KE-Jetronic system in 1986.

[33] In mid-1989 the Bosch system was replaced by Delco GMP4 electronic fuel injection that included a crank-fired wasted spark ignition that eliminated the need for a distributor.

The 920 was originally exclusive to the Italian market, where cars with engines smaller than 2.0 L fall into a lower tax regime.