The next year Italian-American Ralph DePalma came within two laps and a broken piston of victory after a dominant performance in a GP Mercedes.
By 1913 representatives of the American Automobile Association had successfully wooed European participants and Peugeot’s Jules Goux took the spoils.
Domination by European GP machinery continued: Delage’s René Thomas (1914); the tweaked-by-Packard Mercedes of DePalma (1915); Italo-Brit Dario Resta’s Peugeot (1916 – when the race was a 300-miler); and Howdy Wilcox (1919) in a Peugeot prepped in America.
By the time DePalma set pole for the 1920 race in a French Ballot – the car that set a global template for straight-eight racing engines – Indy was ahead of the curve by being the first race for a 3-litre ‘International Formula’.
America was ahead of the curve, too: in 1921 San Francisco-born Jimmy Murphy won for Duesenberg the first GP held for these same regulations: the French GP at a rock-strewn Le Mans.
Although the racing continents would drift apart during the Roaring Twenties as Indy became increasingly specialised and easily big enough to stand on its own four turns, the 500 was included in European governing body AIACR’s World Championship for Manufacturers from 1925-’27.
Indy also remained in step by adopting 2-litre and 1.5-litre maximum limits in 1923 (one year after Europe had) and 1926.
It also followed the European lead of supercharging after Mercedes introduced it to the Brickyard in 1923.
But there followed a backlash as new circuit boss Eddie Rickenbacker introduced in 1930 what would become known as the Junk Formula. Its ethos aped Europe’s Formule Libre era of 1928-’33.
Junk failed in its aim of attracting mainstream manufacturers but helped steer the 500 through the Great Depression.
By 1938 the US economy had recovered sufficiently for Indy to align with the new 3-litre supercharged/4.5-litre normally aspirated GP formula. Shaw’s Maserati won in 1939 and 1940, and would have made it a hat-trick but for a collapsed wire wheel.
The continents drifted apart once again post-World War II as Europe halved its supercharged limit for GP cars.
Ascari’s 4.5-litre Ferrari 375 was – at least when it was shipped to the States – compliant on both sides of the Atlantic. Its V12 suffered from a lack of torque, however, and the Italian star did well to qualify 19th but would be an early retirement because of a collapsed wire wheel.
That same year a turbocharged 6.6-litre diesel started Indy from pole position.
The continental drift continued when F1’s revival in 1954 meant the introduction of a 2.5-litre limit for normally aspirated engines and 750cc for forced induction.
There was some movement on engine capacity at Indy in response to Vukovich’s death and AAA’s backing away from motor sport in 1955 when new governing body USAC trimmed limits to 4.2 litres and 2.8 litres supercharged in 1957.