Perhaps the Lima’s greatest departure from previous Ford engines was its cylinder head design, described as “Poly angle, canted valve, quench-chamber cylinder heads.” These heads feature huge, round intake ports feeding 2.08-inch intake valves, while gasses are expelled through 1.66-inch exhaust valves. In typical Ford fashion, the exhaust ports, while large, are less efficient than the intakes. This is likely unavoidable when engineering such a large engine to fit the engine bays of a number of various models in the Ford-Lincoln-Mercury line. The first 429 ci developed 360 hp at 4,600 rpm and 480 ft-lbs of torque at 2,800 rpm. The 460 ci pumped out 365 hp at 4,600 rpm with 500 ft-lbs of torque at 2,800 rpm.
The most obvious outward difference between the 429 Cobra Jet and Super Cobra Jet engines is the carburetor. The Cobra Jet mounts a 715-cfm Rochester 4-barrel (left), while the Super Cobra Jet features a 780-cfm Holley (right). (Photo Courtesy Lee Lundberg)
While the 460 ci remained virtually unchanged for 1970 and continued to power a wide range of models, the 429 ci took a big step up with a performance version designed to fill the shoes of Ford’s early FE series big-block high-performance engines. The high-performance version of the 429 ci would inherit the storied name “Cobra Jet,” and for 1970, was forced to share this most famous of all Ford performance monikers with the last of the hot FE engines, the 428 Cobra Jet. And like the 428 ci before it, the new 429 ci was available in Cobra Jet and Super Cobra Jet versions.
The Cobra Jet engine featured a cylinder block with either two- or four-bolt main bearing caps according to production date (all 1971 Cobra Jet blocks are said to have four-bolt caps), cast crankshaft, forged-steel connecting rods featuring 3/8 bolts with spot faced seats, 11.3:1 compression, cast-aluminum pistons, 2.25-inch intake and 1.72-inch exhaust valves, a hydraulic lifter camshaft, 1.73:1 non-adjustable sled-type fulcrum rocker arms with screw-in studs, and pushrod guide plates. Up top, a cast-iron intake manifold mounted a spreadbore 715-cfm Rochester 4-barrel carburetor. This combination provided a rated 370 hp with 450 ft-lbs of torque.
A 429 ci that has come to be known as the Super Cobra Jet is at the top of the performance ladder for 1970. Interestingly, a prospective buyer couldn’t just walk into a Ford dealer and order up a car equipped with the Super Cobra Jet 429, since there was no delineation between the two versions of the engine other than an option block for Drag Pack, which listed either a 3.91 or 4.30:1 rear axle ratio. When either of these optional ratios was selected, the buyer also got a 429 cylinder block with four-bolt main bearing caps, forged-aluminum pistons (compression ratio remained the same at 11.3:1), a mechanical camshaft with adjustable rocker arms, an oil cooler, and a cast-iron intake mounting a 780-cfm Holley 4-barrel carburetor. Rated horsepower for the Super Cobra Jet jumped up a conservative 5 hp to 375, while torque remained the same at 450 ft-lbs.
Sadly, the performance era for the 385-series engines, at least from the factory, was short lived. The 429-ci engine lasted until 1973, and by the time of its demise, the mighty motor that once proudly bore the name Cobra Jet had shrunk to a shadow of its former self. Thanks to a reduction in compression ratio to 8:1, smaller valves, larger combustion chambers, anemic camshafts, and all the other trappings of a “smog motor,” the last 429 ci was rated at just 198 hp at 4,400 rpm with 320 ft-lbs of torque coming in at 2,800 rpm.
The 460 would soldier on as a luxury barge and truck engine until 1997, though the last version showing even a hint of grunt was the 1973 Police Interceptor. It used an 8.8:1 compression ratio to help deliver a rated 269 hp at 4,600 rpm with 388 ft-lbs of torque at 2,800 rpm—not even close to the 365 hp and 500 stump pulling ft-lbs of torque made just four years prior.
Thankfully, the tremendous strength, torque, and horsepower potential of the Lima series engines was immediately recognized by the aftermarket performance parts industry, and eventually Ford Racing Performance Parts as well. This resulted in the development of a myriad of performance parts that has resulted in the long-lived popularity of the 429- and 460-ci engines in numerous motorsports venues from street performance to all-out drag racing.
While very similar in appearance and identical in function, there are minor differences between the ram air shaker assemblies on the 429 Cobra Jet (left) and Super Cobra Jet (right) equipped cars, which the trained eye can quickly identify. (Photo Courtesy Lee Lundberg)
Safety First
Safety first: here, now, and always. Anytime you are working around a running engine, there is danger created by moving parts and if you are absorbed in the task of diagnosing a problem or tuning the engine, it is easy to become distracted and get hurt. Prior to starting the engine, perform a walk-around as the pilot of an airplane does before takeoff. This will alert you to anything that may accidentally come in contact with the moving parts of your engine, particularly the fan, belts, and related accessories. Pay particular attention to your clothing. Avoid wearing loose-fitting clothes or jewelry that might become entangled in moving parts and result in injury. Protect your eyes against flying debris by wearing safety glasses or goggles. Do not start the engine until you are satisfied that it is safe to do so and remain vigilant and aware at all times once the engine is running. It is always a good idea to set the parking brake and chock the wheels of a car that will have its engine running while no one is behind the wheel.
Note: As you read on, you’ll learn the engine we are rebuilding for this book came out of a limited-production 1970 Torino. These particular cars received modifications for use as pace cars in the NASCAR racing series, one of which was the installation of a mechanical oil pressure gauge.
Usually the first sign of a loss in oil pressure in cars equipped with the original equipment manufacturer (OEM) light will be the ominous tapping of hydraulic valve lifters as they begin to collapse. Even if you don’t want to invest in a full-time, dedicated mechanical or electrical oil-pressure gauge, there is an alternative available for diagnostic purposes. For many years I have kept an inexpensive aftermarket mechanical oil pressure gauge and an assortment of adapter fittings in my toolbox for just such occasions. If I encounter an idiot-light-equipped car, I merely remove the oil pressure switch from the engine (on Lima series engines this switch is located on top of the block just behind the intake manifold) and use my adapters to tap in the mechanical gauge and take oil pressure readings.
Oil pressure readings should be taken with the engine cold and then again at normal operating temperature, at idle and off-idle conditions. Pressure readings of higher than 20 psi at idle with the engine at normal operating temperature are usually considered adequate, and you should note an immediate increase in the pressure reading without fluctuation as engine RPM is increased.
If your engine has low oil pressure, the causes may run the gamut from dirty oil with decreased viscosity to a clogged filter or passage in the engine’s lubrication system, to something more critical such as excessive main or rod bearing wear. Even though the rotors in an oil pump can be subject to wear or failure, I have found that the oil pump is very seldom at fault when an engine has lost oil pressure. Of course, I still make it a habit to swap out the oil pump for a high-volume pump any time I rebuild an engine.
Decrease in Performance
Just because fuel economy and engine performance have decreased does not necessarily mean your engine has worn out and is in need of a rebuild. There are various causes for loss of power and fuel economy, some of which do not directly relate to the condition of the engine. A clogged or restricted exhaust system could be the cause. Ascertain if the exhaust manifold heat riser is stuck in the closed position, there is a collapsed or kinked pipe in the system, or the catalytic converter is faulty. Something as simple as a dirty fuel filter, carburetor, or fuel injector will restrict