Today we go back in time a bit when motors weren't specified by the sanctioning body, yet one was so dominant there was nearly no competition with it for decades.
When power was king and reliability his queen, the racing countryside was ruled by the 'house of Offenhauser'. From the mid-1930s through the 1970s, the nearly bulletproof Offy dominated the American midget and sprint car scenes and also won the Indianapolis 500 27 times; 1935, '37, '41, '47-'64, '68, '72-76. It remains to this day the all-time leader in wins at Indy.
Its design lineage is traced back through the early 1920s in motors (and chassis) produced by Harry Miller, also famous for his wins at Indy. Miller's cars and/or engines won 12 times in Indianapolis; 1922-'23, '26, '28-34, '36, '38, Miller's design was based on a successful Peugeot motor design that won Indy back in 1913, '16, and '19. Personal bankruptcy forced Miller to sell his assets and Fred Offenhauser (Miller's 'understudy') bought the rights and continued to develop the motor with the help of shop designer and draftsman Leo Goosen.
Now with the tangible bits of its racing heritage fading, I thought it would be great to hear that sound again. That wonderfully majestic rumble and deep staccato of the four (yes, just four massive) cylinders of over 1 liter in displacement EACH and double-overhead cams that frighten with noise, leaving no doubt as to the power that lies within. Ever-popular with gearheads and collectors to this day, many still exist and are refurbished to working (racing) condition from midgets to collectible race cars that parade at festivals such as Goodwood.
Here's a video which reproduces the signature engine sound quite well, but honestly, nothing beats hearing them (and smelling them) burn methanol in person. For extra fun, put on some quality headphones, turn the volume up, and enjoy a trip back to the Kingdom of Offenhauser...
Here's a nice bit of history I found on the interwebnettubes: an audio recording (with slide show of 60s-era cars) of the start and first laps of the 1963 race. If you must (he said begrudgingly) skip the golden voice of Tom Carnegie, Tony Hulman's Command, and the parade laps, then go to the 6:50 moment to hear the field of 33 (26 Offys, 3 Novis, 2 Fords, 2 Chevys) coming at you in full song which certainly tell a race fan they were in the right place...
Currently the rights the Offenhauser legacy and many Offy rebuilds are held by Van Dyne Engineering in Huntington Beach, CA. A nice tribute site to the Miller-Offy legacy also exists here, with a concise racing engine history of Harry Arminius Miller here.
Anyone else care to dream about the moonlight on the Wabash tonight? I know I will.