Donovan developed the 417 cu in (6,830 cc) hemi-head V8 to overcome the tendency of 392 cu in (6,420 cc) Chryslers, then used by Top Fuel racers (many of them friends and customers of his), to crack their iron blocks.
[2] Donovan milled all the internal oil and water passages, and (unlike the stock 392) sleeved the block with chrome-moly cylinder liners, which were stronger as well as easy to replace.
[2] Donovan also enlarged the supports for the main bearings, which Chrysler would do with the B-block.
Donovan completed work on the engine in 1970, and first sold it in 1971;[2] the first driver to use a Donovan hemi was "Kansas John" Wiebe, at the 1971 NHRA Super Nationals, where Wiebe very nearly won Top Fuel.
[4] In 1977, Donovan persuaded "Big Daddy" Don Garlits to switch from the 426 hemi he had been using for the last thirteen years to the 417 cu in (6,830 cc), offering (in Garlits' words), “an engine deal I couldn’t refuse”.