Editing Indianapolis 500 (section)

===Miller and Offenhauser===
[[File:Mercedes w154 indianapolis.jpg|thumb|left|The [[Mercedes-Benz W154]] entered by Don Lee at the [[1947 Indianapolis 500]] with [[Duke Nalon]] as driver]]

Following the European trends, engine sizes were limited to {{convert|183|cid|cc|abbr=on}} during 1920–1922, {{convert|122|cid|cc|abbr=on}} for 1923–1925, and {{convert|91|cid|cc|abbr=on}} in 1926–1929.<ref name="Kettlewell, p.1014" /> The 1920 race was won by [[Gaston Chevrolet]] in a [[Frontenac Motor Corporation|Frontenac]], prepared by his brothers, powered by the first eight-cylinder engine to win the 500.<ref name="Kettlewell, p.1014" /> For 1923, riding mechanics were no longer required.<ref name="Kettlewell, p.1015">Kettlewell, p.1015.</ref> A [[Supercharging|supercharged]] car, ID, first won the race in 1924.<ref name="Kettlewell, p.1015" /> In 1925, [[Pete DePaolo]] was the first to win at an average over {{convert|100|mph|km/h|abbr=on}}, with a speed of {{convert|101.13|mph|km/h|abbr=on}}.<ref name="Kettlewell, p.1014" />

In the early 1920s, Miller built his 3.0-liter (183 in<sup>3</sup>) engine, inspired by the [[Peugeot]] [[Grand Prix motor racing|Grand Prix]] engine which had been serviced in his shop by [[Fred Offenhauser]] in 1914, installing it in [[Jimmy Murphy (racing driver)|Jimmy Murphy]]'s [[Duesenberg]] and allowing him to win the 1922 edition of the race.<ref name="INDY5" /> Miller then created his own automobiles, which shared the 'Miller' designation, which, in turn, were powered by supercharged versions of his 2.0- and 1.5-liter (122 and 91 in<sup>3</sup>) engine single-seaters, winning four more races for the engine up to 1929 (two of them, 1926 and 1928, in Miller chassis).<ref name="INDY6">{{cite web|title=1926 Miller 91 FWD|url=http://www.supercars.net/cars/2458.html|url-status=dead|archive-url=https://archive.today/20130223173430/http://www.supercars.net/cars/2458.html|archive-date=2013-02-23|publisher=Supercars.net}}</ref> The engines powered another seven winners until 1938 (two of them, 1930 and 1932, in Miller chassis), then ran at first with stock-type motors before later being adjusted to the international 3.0-liter formula.

After purchasing the Speedway in 1927, [[Eddie Rickenbacker]] prohibited supercharging and increased the displacement limit to {{convert|366|cid|cc|abbr=on}}, while also re-introducing the riding mechanic.<ref name="Kettlewell, p.1015" />

In 1935, Miller's former employees, Fred Offenhauser and [[Leo Goossen]], had already achieved their first win with the soon-to-become famous 4-cylinder [[Offenhauser]] or "Offy" engine. This motor was forever connected with the Brickyard's history with a to-date record total of 27 wins, in both naturally aspirated and supercharged form, and winning a likewise record-holding 18 consecutive years between 1947 and 1964.<ref name="INDY7">{{cite news|title=All time Indianapolis 500 winners|newspaper=USA Today|url=http://sports.usatoday.com/2015/05/24/all-time-indianapolis-500-winners/|access-date=December 31, 2016|archive-date=September 30, 2020|archive-url=https://web.archive.org/web/20200930222129/https://sports.usatoday.com/2015/05/24/all-time-indianapolis-500-winners/|url-status=dead}}</ref>