1963 Aluminum 377 Small-Block Chevy Engine

Before the 1969 427 ZL1, there was the All-Aluminum 377 Small-block Chevy!

Dateline: 5-7-21, This story by K. Scott Teeters was first published in the October 2019 issue of VETTE magazine – In the early 1960s, an aluminum performance engine was as exotic as fuel injection, independent suspension, and four-wheel disc brakes. The first mention of an all-aluminum engine for a Corvette was in Zora Arkus-Duntov’s proposal outline for the Q-Corvette in 1957. Ed Cole was Chevrolet chief engineer from 1952 to 1956 and was the lead engineer in the design and development of the small-block Chevy.

The Wintersteen L88 Grand Sport #002 resides at the Simeone Museum in Philadelphia, PA. Part of the collection includes the hand-made #002 Roadster replica body and one of the all-aluminum 377 SBC engines that Dr. Simeone purchased from Jim Jeager. The replica body is mounted to a chassis buck with an interior.

Cole was a mechanical engineering visionary. After he became Chevrolet’s general manager in 1956, Cole announced his 1960 Q-Chevrolet concept that would put a transaxle into every car to improve traction and handling and eliminate the transmission hump that would open up the interior. Cole’s plan included the Corvette.

Even before going to work for Chevrolet, all Duntov wanted to do was to build racecars. Based on his racing knowledge, Duntov’s Q-Corvette was spectacular and included; a four-speed transaxle, four-wheel independent suspension, four-wheel disc brakes, and an all-aluminum fuel injected 283 engine. Duntov is usually credited with the all-aluminum small-block Chevy, a deeper look tells a slightly different beginning.

The design parameters of Cole’s SBC were that the engine should be; small, lightweight, simple, and inexpensive. Cole reasoned that an aluminum version of the SBC using a new aluminum-silicone alloy would be obviously lighter and probably less expensive to make. To keep costs down, there would be no valve seat inserts, no pressed-in valve guide inserts, or cylinder liners. But sometimes a simple idea turns out to not be so simple.

Problems started right from the beginning. The complex molds used sand cores and the completed castings required extensive machining. Sand-cast aluminum is high in porosity and low in density. During machining, cavities would open up in the castings, causing a high rejection rate, which drove up the cost.

Another indication that this is likely to be one of the Nassau Invasion 377s is the chrome stamped steel valve covers. Photos in the “Corvette Grand Sport” book by Paddock and Friedman from the race show the same valve covers.

Aluminum pistons on aluminum bores were hard to lubricate and would scuff the bores. Between the strength of materials and the casting challenges, pouring aluminum into molds designed for cast iron wasn’t going to work for mass production.

Weber carbs were THE hot setup in the 1960s before fuel injection became more efficient. The 377 used four massive 58mm side-draft carburetors. The “EW” on the float chamber cover stands for Edoardo Weber, the founder, and inventor of the Weber carburetor.

A few aluminum engines were completed. Duntov installed one in his CERV-I car in 1959, but the valves would freeze to the guides when the temperature went low. Mickey Thompson got an aluminum engine for an Indy car project and bored the cylinders to installed steel sleeves to reduce the C.I.D. to the Indy limit of 255-C.I.D.

Note the non-stock location of the alternator. This was to slightly lower the car’s center of gravity.

Roger Penske had TRACO modestly build an aluminum SBC to just 300-horsepower for his Cooper Monaco. When TRACO was done, the engine weighed just 350-pounds; the lightest of all the aluminum SBCs.

Forensic evidence gleaned from the book, “Corvette Grand Sport” by Paddock and Friedman indicates that based on the shape of the collector on the headers, this was most likely one of the engines used during the Nassau assault in 1963.

The original SBC was never designed to be cast in aluminum. So when exact copies were cast in aluminum, the basic weaknesses of the original design were obvious. In 1960 some Corvette brochures offered 275 and 315-horsepower fuel injection engines with aluminum heads but were canceled early in production due to breakage. Briggs Cunningham was to be given several sets of aluminum heads for his Corvette Le Mans assault, but none were installed.

When Duntov started planning his Lightweight Sting Rays in early 1962 to battle Shelby’s Cobras, the SBC had 327-cubic-inches. Duntov insisted on an all-aluminum 327, reasoning that the heavy-duty parts from the L84 Fuelie would be more than enough for his racing engine. Unlike the previous aluminum engines, steel cylinder liners were pressed into the block. After each block was machined, it was water-tested for leaks. If leaks couldn’t be fixed with welding they were scrapped.

The most significant change to the basic block was that the main bearing webs were thicker and four-bolt main bearing caps were used. The earlier aluminum SBCs were not delivering any significant power increases, so it was decided that more cubic inches were needed. A 4.00-inch stroke yielded 402-cubic-inches. However, experimentation showed that the engine was happier with a 3.75-inch stroke that yielded 377-cubic-inches. Notches had to be made into the insides of the block for connecting rod clearance.

Numerous cylinder head designs were considered. The wildest was a hemi head design with two spark plugs per cylinder. The hemispherical combustion chamber allowed for larger 2.20-inch intake and 1.72 exhaust valves. The intake system was a Rochester constant-flow fuel-injection unit. This was Duntov’s preferred engine for his Lightweight but never was developed or tested. Engineers expected 600-horsepower from the 402-cubic-inch configuration.

The Mark II big-block with its unique “porcupine” semi-hemi heads was in development, so engineers designed and cast similar sets of aluminum heads for the SBC. Initial tests showed that they did not flow as well as the standard wedge combustion chamber heads, so the concept was dropped. If the heads had been developed they could have been a game-changer and made it into production cars.

Twelve aluminum 377 blocks were successfully machined and designated “A” to “L”. When John Mecum took delivery of three Grand Sport Corvettes as part of his Nassau invasion, the cars had aluminum 377s with four 58-mm Webers. After the Grand Sports stomped the Cobras at Nassau, the cars were bought and sold at a brisk pace.

Engineers learned that the aluminum 377s were good for short races, such as Nassau, but not durable for long races, such as Sebring. When Penske raced Grand Sport #005 at Sebring in 1964, his car was powered by a steel version of the 377 and performed very well.

Several of the engines were sent to Jim Hall and installed into his Chaparrals. Hall was instructed to install the engines and not to change anything except for timing and settings for the Webers. The engines were plugged in, raced, and returned to Chevrolet for evaluation.

The inscription of the transmission is unusual and indicates that it was likely to have been a specially built unit. “W.O.26310” could have meant “Work Order”. “TRANS #7-B” could have meant the second rebuild of transmission #7. Also note that the bolts on the case side plate are aircraft safety wired. A special team at Chevrolet built all of the 377 engines, the safety wiring was likely a deterrent to tampering.

As the engines were raced, eventually nearly everything either failed or upon examination was soon to fail. For instance, when one engine threw a rod, engineers used a new process for making rods called, Vacuum-Induction Melt steel to insure no impurities in the raw forging. When bolts were magnafluxed and showed signs of stress, all bolts were then over-designed. Rocker-arm lube was another issue and there were electrical problems with the early-transistorized regulators and ignition amplifiers.

Note the serial number on the back of the block casting, “0240983” and the casting date, “8-20-63”. This “could” have been one of the engines used in the 1963 Nassau assault in early December 1963 that stomped on the Cobras.

Exhaust headers were showing signs of cracking at the ports due to metallurgical problems. This was fixed by using a different welding process. Camshaft gears were failing when dry-sump oil systems were installed. Excessive stress and wear on the camshaft drive gear caused the distributor to retard the timing; causing a drop-off in power.

Privateers raced all of the Grand Sports and many changes were made to the cars. One of the previous owners of the Simeone 377 built this expanded capacity oil pan. Original versions of the engines used as many stock performance parts as possible

The perceived advantage of the all-aluminum SBC was weight; the complete engine weighed 150-pounds less than a cast iron version, however, the aluminum engines didn’t make quite as much power. Because durability was such a serious issue, in the early years, development work went into durability.

Eventually, the aluminum SBC reached optimum development, priced itself out of racing, and didn’t contribute any parts that went into production engines. Close to the end, there was talk of an overhead-cam kit for the SBC, but no action was taken. The amount of money spent on the program was an accounting nightmare for sure. At best, all the problem-solving saved years of development time for the all-aluminum Can-Am block and the ZL1. In a sense, the all-aluminum SBC was a prehistoric ZL1, domed by the basic “bread and butter” design of the original SBC. – Scott


Reproductions of this post’s lead illustration of the All-Aluminum 377 Small-Block Chevy and the Grand Sport #005 are available as 11″ x 17″ prints, signed and numbered by the artist, CLICK HERE!


And for fans of the 1963 Grand Sport Corvette, we have LOTS of Grand Sport Corvette prints CLICK HERE!


 

Corvette Chiefs, Pt. 1 of 5 – Zora Arkus-Duntov, Corvette’s Nostradamus

Duntov carried the heart and soul of the Corvette into racing and created an American legend.

(Dateline: 7-3-20 – This story was originally published in the now-defunct Vette magazine, June 2019 issue) Arguably, there had never been a chief engineer of an American car the likes of Zora Arkus-Duntov. When Duntov was hired to work at Chevrolet on May 1, 1953, the 43-year old European-trained engineer brought a background that made him uniquely qualified to become Corvette’s first chief engineer.

As a young man, Duntov was into boxing, motorcycles, fast cars, and pretty girls. After his formal engineering training in Berlin, Germany, Duntov started racing cars and applying his engineering skills to racecar construction. In 1935 Duntov built his first racecar with help from his racing partner Asia Orley; they called the car, “Arkus”. Their goal was to debut the car at the Grand Prix de Picardie in June 1935. But after a series of mishaps, the car caught fire and never raced. From this point forward, all Duntov wanted to do was build racecars.

Image: GM Archives

In the 1930s Auto Union and Mercedes built the best racecars in Europe. Duntov wrote a technical paper about a new racing concept for the German Society of Engineers titled “Analysis of Four-Wheel Drive for Racing Cars”. at the 1937 Automobile Salon in Paris, Duntov met Dr. Ferdinand Porsche, the designer of the Mercedes-Benz SS and SSK racers, and French performance-car builder and designer, Ettore Bugatti. Mercedes-Benz cars were complex engineering marvels, but Duntov appreciated Bugatti’s elegant simplicity, raw speed, and the success of his cars with privateers. “Simplicity and privateers” are two hints of things Duntov would later do with Corvettes.

Image: CorvetteForum.com

After marrying Elfi Wolff in 1939, war broke out in Europe, and Duntov and his brother Yura had a brief stint in the French air force. France fell quickly and Duntov and his family made their way to New York. The brothers setup the Ardun Mechanical Corporation and worked through the war years as parts suppliers for the U.S. military. After the war Duntov and Yura turned their attention back to racecars and started producing their Ardun Hemi Head Conversion kits for flathead Fords.

Post-war years were difficult and by the early ‘50s Duntov was looking for an engineering job with a major Detroit car company. His goal was to find a company that would let him build racecars. When Duntov saw the first Corvette at the 1953 Motorama, he immediately pursued GM, specifically to work on the new Corvette. Chevrolet general manager Ed Cole hired Duntov and assigned him to work under GM suspension master, Maurice Olley; the clash was immediate. Olley was reserved and a numbers-cruncher; Duntov was outgoing and designed by intuition. Six weeks after being hired, Duntov requested time-off to race a Cadillac-powered Allard JR at The 24 Hours of Le Mans. Olley refused, but Cole got him off the hook to race at Le Mans, but without pay. Duntov was so irritated that he almost didn’t come back from France. After his return, Duntov reassigned and started testing special parts to improve the Corvette’s suspension and general performance.

Image: GM Archives

When the 265 small-block became available in 1955, Duntov took a modified ’54 Corvette with the new engine and some aero mods to the GM Phoenix Arizona test track where he was clocked at 162-mph. The mule Corvette was later rebodied as a ’56 Corvette and was part of a team of three Corvettes that were taken to the 1956 Speed Weeks event at Daytona Beach where Corvettes set speed records. Then in March at the 1956 12 Hours of Sebring race, Corvette scored its first major class win. Duntov and three-time Indy 500 winner and engineer Mauri Rose were then tasked by Ed Cole to design, develop, and make available, special Chevrolet-engineered racing parts. When the Rochester Fuel Injection option was released in 1957, RPO 684 Heavy-Duty Racing Suspension was there for privateers that wanted to race their Corvette.

Illustration & Graphics – K. Scott Teeters

The Bugatti pattern was laid down; make simple, fast cars, and let the privateers do the racing. Duntov also built a few purpose-built Corvette racecars. The 1957 Corvette SS was a good first step but the timing was bad because of the 1957 AMA Racing Ban. The Grand Sport was similar to the RPO Racer Kit program, only a complete, basic racing Corvette was to be sold to privateers. Again, the AMA Racing Ban killed the project. If Duntov hadn’t pushed racing, the Corvette would have morphed into a Thunderbird-like four-seater and been killed by the early ‘60s.

Duntov laid out three design concepts that took decades to implement. The first was his proposal for the 1957 Q-Corvette. This design called for the following: an all-aluminum, fuel-injected small-block engine, four-wheel independent suspension, four-wheel disc brakes, and a transaxle. This design concept arrived in 1997 as the C5.

The second design concept was the mid-engine layout. Duntov’s first mid-engine concept was the 1960 CERV-I. The design parameters were those of an Indy 500 racecar, but with a larger engine. Duntov’s second mid-engine car was the 1964 CERV-II. The third concept in the CERV-II was its unique four-wheel-drive system. Using transaxle parts from the Pontiac Tempest, the system “worked” but would not have lasted as a racecar.

Through the ‘60s several other mid-engine “Corvette” cars were built, but not by Duntov. Engineer Frank Winchell’s 1968 Astro-II Corvette was a beautiful attempt, but like all mid-engine Corvette proposals, it went nowhere. In 1970 Duntov showed his XP-882 with a transverse-mounted 454 engine. After the car was shown at the 1970 New York Auto Show, it went into hiding for some reason. Later, the chassis was used to build the Four-Rotor mid-engine Corvette that was later retrofitted with a small-block engine and rebranded “Astrovette” in 1976, after Duntov retired.

Image: GM Archives

Just after the debut of the C7, the Corvette community started buzzing about the mid-engine C8. For a time the C8 was an unconfirmed rumor until Chevrolet announced that, yes, a mid-engine Corvette was in the works. In 2018 camouflaged mule cars started being seen on public roads. In July 2018 a camouflaged C8.R was seen being tested. Towards the end of 2018 speculation was that the C8 would debut at the 2019 Detroit Auto Show. Then in December 2018, Chevrolet announced that the C8 would be delayed “at least six months” due to “serious electrical problems.”

An insider friend has been telling me for over a year that they were having serious problems getting the car right, but he wasn’t specific. Then another hint was dropped; the problem is with the car’s 48-volt electrical system. Why would the C8 have a 48-volt system? Answer; because it will have auxiliary electrical front-wheel drive. Suspension and traction is everything, so AWD is inevitable.

Illustration & Graphics – K. Scott Teeters

While Duntov didn’t “predict” the Corvette’s future, he certainly set the course. His insistence that Corvette be tied to racing, kept the car from becoming Chevy’s Thunderbird. The features of the 1957 Q-Corvette are the very design foundation of the C5, C6, and C7 Corvette. The CERV I, CERV II, and the XP-882 (minus the transverse engine) will live in the mid-engine C8. And it is likely that the CERV II’s all-wheel-drive concept will live in the C8, only as an electrical, and not a mechanical system. Without one man’s obsession with building racecars, there’d be no Corvette legend. – Scott

Be sure to check out the Duntov installment of my “Founding Fathers, Pt. 4 Zora Arkus-Duntov”, HERE.

Also, catch all 5 parts of my Corvette Chiefs Series

Corvette Chiefs, Pt. 1 – Zora Arkus-Duntov

Corvette Chiefs, Pt.2 – Dave McLellan

Corvette Chiefs, Pt. 3 – Dave Hill

Corvette Chiefs, Pt. 4 – Tom Wallace

Corvette Chiefs, Pt. 5 – Tadge Juechter