WHILE the legendary 426 Chrysler Hemi is without doubt the most famous, it is far from the only Detroit V8 fitted with cylinder heads featuring hemispherical-style combustion chambers. Developed to take on Chrysler’s famous 426 on the high-banked NASCAR ovals, Fomoco’s effort was the Boss 429 – also known as the Shotgun, or Boss ’9. It is believed that less than 1400 were fitted to production cars – namely 1969 and 1970 Boss 429 Mustangs. Ford’s racing partners, Kar-kraft, plus Holman & Moody, fitted Boss 429s to a few other cars, but these were mostly development mules or purposebuilt race cars. Genuine Boss Mustangs are a worldwide collectible, with premium examples fetching in excess of US$400,000. Given the engine’s scarcity due to low production numbers and the collector value of restored Boss-powered machines, factory engines are all but impossible to find. But aftermarket companies like Ford Racing, Eliminator, Kaase and Sonny’s have all tooled up to churn out reproduction blocks and/or cylinder heads – much to the delight of Ford fans the world over.