Photographs Courtest of GM, Russ Gee, The John And Marge Sawruk Collection, and Geneva Campbell
Part 1: Design and development—’55 to ’67
Illustration by David Kimble / Courtesy of GM
Every time you get behind the wheel of your favorite classic Pontiac, you have more than general managers Semon E. “Bunkie” Knudsen, Elliott M. “Pete” Estes, and John Z. DeLorean to thank for the success of its overhead-valve V-8. Before any of these icons in Pontiac’s history became household names among auto enthusiasts, a group of dedicated engine engineers and scientists were working on moving Pontiac out of the world of the Straight 6 and Straight 8 and into the future of the Pontiac V-8.
Herb Adams, the Pontiac special project engineer who counts the ’69 Trans Am amongst his many accomplishments, began as a student draftsman at Pontiac Motor Division in 1957. He recalls learning the stories of the origins and development of Pontiac’s famous V-8 from Motor Engineer Mark Frank, who warmed up to Adams and shared stories with him in 1968.
“I want High Performance Pontiac readers to know and share these stories that Mark told to me, and those that I had firsthand knowledge of during my career at Pontiac,” he says. “These pioneers of the Pontiac V-8 deserve to have their names remembered, for their work formed the basis for all of the Pontiac V-8 engines of the musclecar era and beyond, including the 389, 421, 326, 400, 428, and 455.”
What follows are Herb’s recollections.
Pontiac’s showroom brochure introduced the new-for-’55 V-8 and heralded its power and perf
Title: Assistant Engine Engineer
Accomplishment: Inventor of the Stamped-Steel Ball Rocker Arms
Prior to his invention of the stamped-steel ball rocker arms, the rocker system used on most of the existing overhead-valve V-8 engines consisted of a ground shaft with forged and machined arms pivoting on it. Clayton reasoned that stamped parts—costing pennies—would result in a big savings. This led him to design the famous stamped-steel ball rocker arms.
Clayton couldn’t get his bosses at Pontiac Engineering to let him work on the project, so in classic hot-rodder style, he made the first ones in his home basement machine shop. When he was able to prove to Pontiac Engineering how well they worked, he was allowed to pursue the project on company time.
Once Pontiac Engineering was satisfied with the design, Clayton had to show it to the manufacturing experts within the Division. Since it was a new idea, they told him it was impossible to produce. To prove them wrong, Clayton brought in his garage tooling and showed them how he did it.
To this day, Chevrolet claims it invented the stamped-steel ball rocker arm, and its PR department makes no mention of Pontiac Engineering (though they do credit Clayton, specifically) as its inventor.
A search of U.S. patent records shows that Clayton had more than 20 patents on V-8 engine design, manufacturing, and lubrication. Let’s look at some of the most significant ones, as they relate to high-performance Pontiac V-8s.
U.S. Patent Number 2,902,014: Valve Actuating Mechanism for Engines
This design was pure genius, as it replaced the forged and machined rockers with very inexpensive stamped parts. His patent drawing also shows some other interesting cost savings, such as a pressed-in tapered stud instead of a tapped one, and a stamped hollow ball, which he figured out how to make. It’s another of his inventions that the manufacturing experts said was impossible to produce.
U.S. Patent Number 2,820,267: Cylinder Head / U.S. Patent Number 2902021: Cylinder Block
If you’re not familiar with how a foundry manufacturers blocks and heads, cores are used in the casting process to shape the internal cavities, such as the water jackets. Clayton put his inventive mind to work on these major castings and came up with a simplified method of making the cores for casting the block and heads. Earlier V-8s, such as the Oldsmobile and Cadillac versions, used more complicated cores, which raised the cost of the engine.
What was Clayton like as a person? I remember he was an open and friendly guy who used his charm to cultivate ideas amongst his associates. When I left Pontiac in 1973, he was the Division’s assistant chief engineer.