Mac McKellar

Big Mac to Go

Malcom “Mac” McKellar spent over 40 years as Pontiac’s engine designer

Story by John Gunnell

Pontiac engine designer Malcolm “Mac” McKellar passed away on April 9, 2011 in Florida. McKellar, who was 90 years old then, suffered a stroke and died shortly afterwards. When he died a big part of muscle car history passed away.

If you are into Pontiac performance engineering of the late 1950s or early 1960s, the name McKellar is probably familiar to you. Malcolm R. “Mac” McKellar spent over 40 years of his life—between 1941 and 1982—working as a staff motor engi-

neer for Pontiac Motor Division. During this period, he helped develop high-performance V8s and two unique Tempest series engines. The Tempest power plants were called the “Indy Four” and the overhead cam “Sprint Six.”

When Pontiac started in 1926, its first chief engineer Ben Anibal was known as an engine wizard and set a tradition for the company’s engineers to follow. However, his successor George Delaney, who took the job in 1947, wasn’t an engine specialist. When market pressures forced Pontiac to start developing its first postwar V8 engine, Delaney called on Mark Frank, a staff engineer on engines, to supervise the project and uphold the tradition.

Frank had two assistants who worked closely with him: Clayton B. Leach and Edmund L. Windeler. Leach held an A. B. degree in mathematics from Park College and then attended the GM Institute from 1935 to 1937. He joined Pontiac in 1937, the same year Mac McKellar came aboard GM. Windeler earned his B.S. degree in mechanical engineering from Virginia Polytechnical Institute in 1936, the same year he joined Pontiac as an engineering test driver. He was appointed supervisor of the company’s Power Development Section in 1945.

In the early ‘0s,” Mac” McKellar was turning out hot cams and other engine goodies for cars like this ’2 Catalina convertible. His engine designs helped Pontiac get a firm hold on third rank in industry sales. - photo-credit GM Media Mac’s father—Charles McKellar—worked for General Motors as a foreman at the GM Proving Ground in Milford, Mich. His son got to see some of the cars he brought home and must have been impressed by the Pontiacs, as he bought a used 1937 Pontiac as his first car. It cost the princely

sum of $300. After finishing high school, Mac became a student at the GM Institute and he landed a job in the engine design department in 1941. During World War II, he was drafted into the army, but he returned to his Pontiac job after a 22-month military stint.

In the early postwar years, Pontiac stuck with L-head sixes and eights longer than everyone else except Packard. However, with the success of the Cadillac, Oldsmobile and Buick V8s, the in-line engines were hurting Pontiac sales. The company was interested in developing a V8 engine and Mac was the man to do it. McKellar once told the author that the original plan was to have him design an L-head V8, since that type of engine had fewer parts and was simpler and cheaper to make. Fortunately, experimental flathead engines didn’t breathe as well as overhead valve V8s, so overhead valves got the final nod at Pontiac.

The late John Sawruk, Pontiac’s Official Historian, used to publish hidden facts about the Pontiacs and one of his favourite hidden facts was that the 1953 Pontiac frame has holes in it for mounting a V8 engine. Mac McKellar confirmed that there were plans to use the V8 in 1953, when he spoke to Jan Norbye and Jim Dunne for their book Pontiac The Postwar Years. “It was postponed partly because of design and production problems and partly for economic reasons,” he told the two writers. “We could have had it out sooner, but the feeling was that we had to produce an engine that was economical to build and try to be competitive on price in our segment of the market, as it was envisioned at that time.”

Mark Frank had McKellar design an engine using a wide bore and a short stroke, which was the format GM divisions seemed to prefer in the ‘50s. According to a presentation called “New Pontiac V8 Engine” that Leach and Windeler made at the SAE Golden Anniversary Meeting in Detroit on Jan. 12, 1955, The concept of a Pontiac overhead cam six came out of the Pontiac advanced engineering section run by DeLorean (shown), but it was McKellar who got the job of drawing up the actual production version. - Photo credit GM Media

“Pontiac Motor Division of General Motors hereby decrees the honorary title of Doctorate of Engines Emeritus be conferred on Malcolm R. McKellar in recognition of his proficiency in the engineering of automotive powertrain systems,” says the certificate Jay Wetzel is presenting to Mac. – Pontiac Product Engineering

McKellar played a big role in engineering the original 197 Firebird, a car that was offered with both his overhead cam six and his Ram Air V8. Mac always said he enjoyed working for Pontiac during the division’s performance years.

In 1983, Pontiac Motor Division Product Engineering published a 75th Anniversary hardcover that included this page recognizing Malcolm R. “Mac” McKellar as the “Mastermind of the GTO V8 engine.” - Pontiac Product Engineering Dept. Book

McKellar had four main objectives in his engine design: (1) Outstanding performance with assured adaptability to future fuels; (2) Proven durability, equalling or exceeding its predecessor (the Pontiac L-head straight eight) in all respects; (3) Ready adaptability to displacement increases without major tooling changes and with no compromise to engineering function; and (4) Overall simplicity of design for complete ease of manufacturing and convenient servicing.

The original 287-cid Pontiac V8 was offered in 173-, 180-, and 200-hp options. In 1956, it became the 317 V8 with up to 227 hp. The basic 1957 Pontiac V8 was the 347, but a new 370 fuel-injected V8 was used in the ’57 Bonneville convertible. The 370 was then used in all 1958 models and, in 1959, it became the legendary 389, which came in a bunch of “flavours” up to Tri-Power.

By 1959, Elliott M. “Pete” Estes had taken over as head of Pontiac Engineering. He reorganized the section, making Mark Garlick executive engineer. H.R. Field was chassis engineer and John P. Charles held the title assistant chief engineer in charge of testing and reporting. On the engine side, Ed Windeler was design supervisor and Clayton B. Leach and Mac McKellar were design engineers. John DeLorean was in charge of advanced engineering.

McKellar’s aforementioned “Indy Four” was made around this time by cutting the 1959 Pontiac 389-cid engine in half. In fact, in one early test, McKellar simply put large holes in a 389 V8’s four left-bank pistons and disconnected the valve train parts for those cylinders. Even after those changes, the big Pontiac

McKellar’s engine wizardry was instrumental in turning Pontiacs like this 21-powered Super-Duty Tempest into winners at drag strips across America. Racers from Fireball Roberts to Mickey Thompson relied on his designs.

McKellar arrived at Pontiac long before “Bunkie” Knudsen came aboard in 1957. “Mac” worked on Pontiac’s first overhead-valve V8 that was introduced for model year 1955. - Photo credit GM Media

that the altered engine was in could hit 92 mph and register decent gas mileage.

Norbye and Dunne documented some of the struggles McKellar encountered in getting test versions of the four-cylinder engine balanced. He must have done okay with the job, since the car got good reviews in Motor Trend and Pontiac sold enough Tempests to move the division into third rank in total auto industry sales. It was the best Pontiac had ever done and hopefully Mac McKeller got a raise.

McKellar grew famous among racing fans and muscle car lovers for his design of 12 special and exotic racing camshafts for Pontiac’s factory-built race engines. With his help, Pontiac Catalinas finished 1-2-3 in the 1961 Daytona 500, setting a new record for the race with a winning average of 149.601 mph.

“Back at the factory, Mac McKellar was turning out new and hotter cams faster than if his middle name was Isky,” says Jim Dunne and Jan Norbye in their book. Each of these cams was well-known to enthusiasts by the designer’s name and the number that followed. For example, the McKellar No. 6 cam, of 1961, was a fairly mild type with standard lift, but intake valve duration was extended to 283 degrees and exhaust valve duration was 293 degrees.

The McKellar No. 7 cam, released the same year, was a bit wilder. It had a 0.414-inch lift, 301 degrees intake duration and 313 degrees exhaust duration. It was known as a more temperamental design, but drag racers were concerned as much about driving a high-strung automobile as they were about going fast. And Mac knew how to make Pontiac engines go fast. McKellar-cammed cars tore up quarter-mile strips all across America, as well as a good number of circle tracks. During 1962, J.L. Meador campaigned a Super Duty Catalina hardtop sponsored by Van Winkle Pontiac, of Dallas, Texas. This “Poncho” was equipped with a 421cid 373-hp firebreather with dual NASCAR-type quad carburetors and a McKellar No. 11 camshaft. Clocking 105.75 mph and a 13.59-second elapsed time, the It was said that Pete Estes could ride Waggoner-Meador-Van Winkle Pontiac tore up stock competition in in a car with a blindfold on and pick out its problems and shortcomings. In 1959, Estes took advantage of McKellar’s innate talents and made him his engine design engineer. - GM Media no uncertain manner. Fireball Roberts took the Daytona 500 with a McKellar No. 11 cam under his hood.

Since the Indy Four lacked the power desired for the larger Tempest coming out in 1964, Mac McKellar began work on a new in-line six. He designed an advanced overhead cam six, but GM didn’t allow enough time to fully develop and test the engine. The 1964-1965 Tempest did offer a six, but it was basically a Chevrolet overhead valve engine assembled in Pontiac factories. It was not an exciting engine, but Mac did get to hot rod the 389 for the 1964 GTO.

John Z. DeLorean was a big fan of exotic imported cars and the original design for a Pontiac overhead cam six was sparked by his advanced design group. The design was then given to Mac McKellar for further development and production design

Mac’s work on experimental overhead cam Pontiac V8s was honoured inside and on the cover of the March 198 issue of Hot Rod magazine.

work. McKellar knew that eliminating push rods and rocker arms would give him more ponies at high rpms with adequate torque throughout the speed range and with smooth idle characteristics.

The overhead cam six was so exciting and so well-received that Pontiac had Mac develop some experimental overhead

In his book Glory Days ex-Pontiac ad man Jim

Wangers (right) says McKellar was a member of the Super-Duty group at Pontiac. Their job was to make Pontiacs win on the track. Wangers mentions having lunch with the group. cam V8s, too. “Exclusive: Pontiac’s overhead cam V8s, “ said a headline above the banner of the March 1968 edition of Hot Rod magazine. “Pontiac’s McKellar reveals why OHC V8s may soon be production engines,” read a cover blurb next to a picture of Mac behind a very exotic-looking power plant. McKellar also helped create later Pontiac performance mills, including HOs, Ram Airs and the Super-Duty 455 for 19731974 Formulas and Trans Ams. As Pontiac chief engineer Jay Wetzel noted in 1982, “Mac was the engine architect who led us through Wide-Track, GTO, Tri Power, 400, 421, 455 and Super Duty, followed with 301 and 155 (2.5L) engines.”

When Mac McKellar retired from Pontiac on June 25, 1982, over 160 Pontiac executives, engineers, production experts and supplier reps appeared at his retirement party. Guests in attendance included such people as Jay Wetzel, Bob Newill, Russell Gee, Skip McCully, Steve Malone, Dimitrie Toth, Mike Hicks and the author of this article.

Jay Wetzel, who was Pontiac’s chief engineer between Sept. 1, 1982 and June 1984, presented Mac with a certificate. It started with the wording, “Pontiac Motor Division of General Motors hereby decrees the honorary title of Doctorate of Engines Emeritus be conferred on Malcolm R. McKellar in recognition of his proficiency in the engineering of automotive powertrain systems.”

George Tozar also read letters of appreciation from Clayton Leach, and two former Pontiac general managers that McKellar had worked under, Estes and DeLorean. Bob Dorn, who was Pontiac chief engineer then, said, “Those who have been touched by Mac during their professional careers are very lucky.”

At the close of ceremonies, Mac took the podium and announced that he planned to spend his new found leisure time in the restoration of a 1962 Grand Prix and a year later a Pontiac Bonneville with the 421 HO V8. “As you can tell,” he said. “Old

hot rodders never die; their top speed just declines a little.” 32 MUSCLE CAR PLUS MAGAZINE OCT/NOV 2020