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The following is a brief overview of my account of the evolution of the 426 Chrysler Hemi engine used in Top Fuel and Funny Car. In the mid-1960s and early 1970s, it produced about 2,000 horsepower. Today, the purpose-built nitro-burning Hemi engine produces 10,000 horsepower.
I began my career in NHRA Drag Racing in 1971. I was a mechanic (bottom end) on John Foderaro's Top Fuel dragster driven by Ed Renck. In 1972, we qualified No. 1 at the Supernationals held at Ontario Motor Speedway with an elapsed time of 6.09 and a speed of 227 mph. The engine we used was a 426 Chrysler Hemi. Many of the components were purchased directly from Chrysler and were made out of cast iron.
Now let's fast-forward to 2013, when I had the pleasure of working with Steve Torrence's racing team. We set the 1,000-foot track record for speed at the U.S. Nationals in Indianapolis at 328.38 mph. The engine we used was a purposebuilt 496-cid AJPE aluminum Hemi. I have been very fortunate to have witnessed firsthand the engineering of these engines and their components from the beginning of the 426 Hemi being used in Top Fuel and Funny Car. More importantly is the fact that I personally had the experience of meeting and working with the brilliant minds of the people who engineered and manufactured most of the components during this development.
Engine block
In the mid-1960s, teams began to use 426 Chrysler Hemi engine blocks. They were cast iron, the bore size was 4.250, and the stroke of the crankshaftwas 3.750. In 1974, Keith Black produced his first aluminum version of the 426 Hemi block. It was cast aluminum and had replaceable ductile iron sleeves. This was just what fuel racers needed. The block was repairable, and the sleeves could be replaced if damaged.
Today, the engine blocks are produced from forged or billet aluminum. They are machined on very expensive CNC machines for accuracy. This accuracy has improved the parasitic loss of horsepower because of the perfect alignment of all of the components. The camshafts have been raised from the stock location, the lifter bores have been spread, and the oiling passages have been moved for improved lubrication. The size of the head...