Remembering Sonny Leonard: The Legendary Engine-Builder

Remembering Sonny Leonard: The Legendary Engine-Builder

Estol Fletcher “Sonny” Leonard came from humble beginnings. After proudly serving his country in the US Army, he was hired as a tech at a Chevrolet dealership. However, drag racing and engine building was his passion. He would drag race as a hobby using whatever extra money he could spare. In whatever time there was left, he was building engines and, in 1968, would open up shop in a small 300 square foot building in Madison Heights, Virginia. 

Remembering Sonny Leonard: The Legendary Engine-Maker

Sonny’s Garage, as it was known, will always have a special place in the hearts of all his early customers. Here, he worked on pretty much anything that had wheels. He would work tirelessly to refine and hone his craft, and once he had gained a level of mastery, he decided to expand his business. 


In 1977, he relocated to a 5000 square foot facility. Throughout the late 70s and 80s, Leonard worked on a number of racecars under the alias “Southern Rat”. His work led to some very impressive performance developments. He put together a 540” engine for a up-and-coming racer from the Ohio bracket named Chuck Sneed. He amazed the crowds at the IHRA and AHRA Pro Stock events with his performance, resulting in his induction into the Holley 7-second club. The most impressive development made its way to the headlines in 1987, when Bill Kuhlmann, a customer of Sonny, made history at Darlington. He became known as the first driver to run a bull-bodied car at 200 miles per hour!


Kuhlmann’s performance had a significant impact on racing overall. The demand for bigger and more powerful engine skyrocketed and racers started fitting in as big of an engine a stock block could accommodate at the time. Many thought that engine development had already peaked.


Leonard tackled this problem head-on and made use of aftermarket blocks with larger dimensions. Modifications like larger-bore centers, spread oil pan rails and elevated cam locations allowed for more room. He worked with Donovan Engineering to design the features of an aluminum block.


These developments were followed by upgrades to internal engine components to provide safety under the great stresses of racing. Wider-diameter pushrods and camshafts were introduced to minimize flex, while rod bolts and connectors were crafted using space-age technology for increased strength and endurance. Hot isostatic pressure technology greatly improved the castings for cylinder heads which helped reduce porosity issues while also providing sturdy and lightweight blocks. The end-result was the breakthrough of 1005 cubic inch engine that Sonny later built and developed for a customer overseas.


Over the years, Sonny’s Garage transformed into Sonny’s Racing and honed its focus onto competition engines. As local and international demand for Sonny’s engines grew, the name evolved into Sonny’s World Class Racing.

Sonny Leanard’s professional legacy is that of progressive-thinking and top-quality products. His name alone is enough to establish the credibility of his ingenious creations. His loyal customers continue to revere and remember him for the legend that he was. Personally, he was a kind and loving person. He cared for everyone and looked for ways to help those in need. 

The last update from Leonard was on the 28th December, noting that he was hospitalized due to pneumonia, however, he was showing signs of recovery. The heartbreaking news of his passing was released on 10th of January 2021. He will be deeply missed by all those who were fortunate enough to know him, and his name will be etched into racing history.