Chevy Big-Blocks—the Mark IV and a New 427


Light-duty trucks and some larger vehicles used a 366-cubic-inch (6.0L) version of the Mark IV from the mid 1960s until the mid-’90s. A 396-cubic-inch (6.5L) version of this V8 was available for the Corvette in 1965 as the L78 option as well as for the Z16 Chevelle. The engine had four-bolt main bearing caps, a bore of 4.095 inches (104.0 mm), and the stroke was 3.760 inches (95.5 mm). The 396 version delivered 375 hp (280 kW), developing 560 lbs.-ft. of torque and performs well running in the upper 6000 rpm range. The 402-cubic-inch (6.6L) is a variation of the 396, bored 30/1000 of an inch. This engine sold as a 396 in the smaller vehicles, then marketed as the Turbo-Jet 400 in the full-size automobiles, although light-duty pick-up trucks had the identical engine as the other two but was referred to as the 402.

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For the 1966 model year, the Mark IV engine showed up on the sales floor as the 427-cubic-inch (7.0L), but it was available as a power option on the full-size Chevys and also available under the hood of the Corvette. The bore increased to 4.25 inches (108 mm) ,but depending on where the engine was, the horsepower rating varied.

If the engine was in a family sedan, the car would have a smooth, even idle with hydraulic lifters, but a rough-idling high rpm version with solid lifters was also a choice and often put into a basically equipped unit such as a Biscayne two-door. In the Biscayne with RPO L72, the solid lifter 427 delivered 425 hp (317 kW). The plain Jane, lightweight Biscayne was a sleeper, looked much like a taxicab with two doors, and got the moniker Bisquick.

Beneath the hood of the Corvette from 1967 to 1969, the quintessential version of the 427 Tri-Power was available from the factory as RPO L71. This was three two-barrel carburetors that fed the fuel into the combustion chambers and developed 435 hp (324 kW) although it’s the same engine as the RPO L72 introduced in ’66. However, that version had a single four-barrel bolted to the intake.

Both of the 427 variations featured a high-lift, long-duration, high overlap camshaft, and to increase airflow, the cast-iron heads had large ports delivering more power at high rpm. A review of the Corvette stated the car gave “the ultimate in sheer neck-snapping overkill.” Both the RPO L72 and L71 did a standing start to 60 mph (97 km/h) in less than six seconds with quarter-mile time around the 13.5 second mark, achieving a top speed of 105 mph or better in the process.


Aluminum heads for the L71 were also available as RPO L89, but this option did very little to increase the performance in a straight line. What the option did do was reduce the weight of the vehicle by about 75 pounds, which improved the weight distribution, resulting in improved handling. Super Chevy magazine conducted a chassis dyno test on a factory-produced Copo L-72 equipped Camaro. Although this car was well tuned, it only registered a peak of 289 actual horsepower delivered to the wheels. This test shows just how inaccurate the old style “gross” horsepower ratings actually were.

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Hanging out at the Petersen Museum today ...

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Streamlined roof-mounted emergency lighting pods were beginning to appear by 1940 and Meteor showed a number of ambulances so-equipped in their mailings. Meteor's flower cars were topped by 5-window business coupe-style roofs and featured a fake folded convertible top made of aluminum mounted at the rear of the flower box. Meteor introduced a new driver's door first seen on 1939 S&S carved-panel coaches that featured an unusual A-shaped window frame. Meteor then mounted a miniature coach lamp within the triangular panel that was now part of the body. Although the new arched door looked great on their service cars, flower cars and carved Gothic hearses, it looked hideous when combined with the vertical B & C pillars found on their limousine-style coaches and ambulances. The rear door window frames as well as the B-pillars and C-pillars were still vertically oriented and clashed with the sharply sloping outline of the front door's arched window-frame.S&S did the right thing and used vertical B-pillar front door frames on their regular limousine-style and landau-style hearses and ambulances. Although they could have used a regular door on their limousine-style coaches and ambulances (as did S&S), for some unknown reason, Meteor didn't and continued producing ugly limousine style coaches until 1950, when regular door frames returned.Quite unfairly, LaSalle had acquired the reputation of being a "cheap" Cadillac and was eliminated by GM just as Cadillac released their new Bill Mitchell-designed models in 1941. The new Cadillac was decidedly forward-looking, side-mounted spares had been eliminated and the new Hydra-Matic automatic transmission was available for the first time having been pioneered by Oldsmobile in the previous year. The prow-nosed look seen in the Thirties was gone, replaced by massive front-end highlighted by the now-famous egg-crate grille. Headlamps were now mounted in, rather than on top of, the front fenders. Equipped with a Cord-like coffin-nose hood the new Cadillacs were noticeably different from their predecessors and set the standard for American luxury during the 1940s. A mid-sized 29-passenger transit bus prototype called the 101 was built during 1941, but never saw production. However their experience with the vehicle helped procure a large contract to produce bodies for a post-war Reo transit coach.The A-framed Meteor coaches continued little unchanged through 1942 although a less-expensive series of coaches appeared in 1941 mounted on Chevrolet chassis that featured normal-looking vertically-oriented B-pillars. When seen on a flower car body, Meteor's A-framed front doors looked good and their 1942 version featured a 5-window business coupe roof mounted on top of a standard Meteor coach body that had been built with no structure above the beltline. The coupe's blanked-in rear quarter-windows were covered by a landau bar and the base of the roof flowed straight back to the rear of the flower box which still had a makeshift faux folded-convertible roof. The rear doors were left intact and could be used to load chairs or other graveside necessities. Access to the casket compartment was through the tailgate which had built-in casket rollers that matched those on the compartment floor. The height of the exposed stainless steel flower deck was hydraulically adjustable so that different-sized floral tributes could be accommodated and a tonneau was included to cover the bed when not in use.After an illustrious career with Henney and a short stint at the Des Moines Casket Company, automotive designer Herman Earl (1878-1957) worked for Meteor up until his retirement during WWII. Another famous wartime Meteor employee was John B. Judkins who became a consultant for the firm, when his Merrimac, MA coachbuilding firm folded in 1942. During the War, Meteor manufactured aviation equipment for the US Navy and ramped up for civilian production in early 1945.Immediately after the war Meteor built 969 bus bodies for Reo's post-war 96-HT 'Victory' bus (1945-1947). These Reo-Meteor coaches included a Continental 427cu in 6­cylinder gasoline engine mounted under the floor and featured sectional bodies similar to those produced by Wayne Works.1946-1948 Meteor coaches remained unchanged from the pre-war 1942 models and still included weird A-framed front doors with integral miniature coach lamps. As with other makers, post-war prices increased by about 50% and new Meteor coaches started at $5,000. All Meteor coaches were now built on Cadillac chassis and included rear fender skirts plus optional automatic transmission and air-conditioning. Ambulances could be ordered with built-in roof-top warning lights, a choice of sirens plus a clever front fender-mounted fire extinguisher.Cadillac's new commercial chassis was available beginning 1949, one year after the introduction of their famous P-38 Lightning-influenced rear fenders.

Are the engine and drive train still there?

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I like to see them when their done too.

Thing is really trashed


Greg Andry

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4 weeks ago

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About 60 vintage Vintage parts cars for sale in Michigan. Cadillacs, Olds... ...

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1 month ago

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Super Clean 1966 Chevy Caprice ...

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One beautiful Car. One of my favorites !!!! I wish I had the money to buy it !!!!!!🚦

Had one miss it

Mauricio Costa Augusto Taques

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