Ford 390 History
The Ford 390 is a bored and stroked version of the Ford 352, which was a popular FE motor prior to the introduction of the 360. The 360 and the 390 are marked with “352” on the block, which can be confusing. Many Ford FE motors carry this casting mark on the block regardless of their actual displacement.
The Ford 390 has the same 4.050" bore as the 360, but a longer 3.780" stroke. The 360, which had a 390 block and a 352 crankshaft, can be converted to a 390 by swapping the crankshaft and connecting rods.
The Ford 390 big block debuted across the Ford and Mercury line in 1961. It was considered a high-output motor, and Ford made it available in notable vehicles such as the Thunderbird and the Police Interceptor. The initial models produced 330 horsepower and 427 lb-ft of torque, which was impressive at the time.
Throughout the 1960s, the 390 became a staple performance motor across the Ford line. Horsepower and torque varied over the years, peaking at 401 hp in 1961 and 1962. In 1967 and 1969, the Ford 390 produced 335 hp and 427 lb-ft of torque. The 390 became even more well-known in 1967 thanks to the Ford Mustang.
The engine gave vehicles a performance edge from the factory, and it became an extremely popular platform for hot-rodding. Though not as powerful as the 427 and 428, the 390 was still a respectable power plant in muscle cars like the Ford Mustang and the Mercury Cougar.
Ford 390 Specifications
ENGINEFORD 390 FE BIG BLOCKMANUFACTURERFORDYEARS PRODUCED1961 to 1976DISPLACEMENT390CI (6.4L)CONFIGURATIONBIG BLOCK V8FUEL TYPEGASOLINECOMPRESSION RATIO10.5:1FIRING ORDER1-5-4-2-6-3-7-8BORE4.05 INCHES (102.87 MM)STROKE3.785 INCHES (96.14 MM)HORSEPOWER (1963)250 HP (190 kW)TORQUE378 LB-FTGAS MILEAGE10-17 MPG (EST)
Demise of the Ford 390
The 390 lived a relatively short life, as it arrived too late in the era to match the long life of Ford's versatile Windsor motors. With the 1970s fuel crisis and Federal emissions standards looming, the market began to move towards more efficient small block V8 engines.
The Ford 390 was phased out of use in passenger cars in 1971, though it found a niche as a durable and torquey pickup truck motor until 1976. It served this role well, and there are still many Ford trucks on the road with 390 engines.
Cars Equipped With the Ford 390
The Ford 390 was once a popular passenger car engine. It was installed in numerous Ford and Mercury sedans, coupes, and wagons between 1961 and 1971. The most notable early use of the 390 was in the Ford Thunderbird, where it was offered between 1961 and 1968. Other Ford cars that came with the 390 big block include the Mustang, the Fairlane, Ford Police Interceptor, and the Torino.
The big block 390 was used across the Mercury line as well. It appeared in notable vehicles such as the Mercury Cougar, Mercury Comet, and the Mercury Cyclone. The Ford 390 engine was considered a higher-level performance motor at the time, so it was often sold under the GT trim level. Vehicles such as the Mercury Cyclone GT and the Mercury Cougar GT fall into this category.
Ford 390 Use in Trucks
The Ford 390 was used extensively in trucks during the 1960s and 1970s. In fact, most trucks of that era that survive have a Ford FE motor. The 390 FE motor was found most often in 3/4-ton Ford F250s, but it was also available in other trucks.
Ford phased out all FE truck blocks around 1975-6 in favor of the “smogger” Modified (M) and Cleveland blocks. The Ford 360 FE was also very common in trucks, especially half-ton F100s across all trim levels.
The 390 was available for the F100 into the 1970s, but it’s a relatively rare option. Many of these trucks came with a 360, and owners often stroked it to 390 cubic inches, as this was a relatively straightforward way to boost power.
Is the Ford 390 a Good Motor?
The Ford 390 is a very durable engine, and many people swear by it. That said, it’s inefficient, and performance parts are pricier than most. But with proper care, these powerful engines can run forever.
Some people would describe the 390 as a little bit rough around the edges. There’s some truth to that, as it’s easy to get a 390 running but tricky to get it running just right. It’s an old motor with a clunky design, but it works well in many applications.
Ford 390 Pros and Cons
So, why choose a truck or car with a 390 FE engine? For one, they’re usually pretty easy to come by. Ford stuck this motor in tons of vehicles for more than a decade, and they’re especially common in trucks.
Additionally, these engines are absolute torque monsters. During the 1960s, a stock 390 with a carburetor and cast iron manifolds produced more than 400 lb-ft of torque. Due to the smog laws of the 1970s, it would be decades before a run-of-the-mill car or truck engine would produce anything close to that.
High torque makes Ford 390 vehicles fun to drive and great for hauling, but what’s the tradeoff for all of that power? The obvious answer is fuel economy. The gas mileage of this engine is atrocious. At least with a small block, you can hope to achieve reasonable fuel economy. The Ford 390 big block is a heavy gas drinker no matter what you do to it.
Ford 390 Performance Parts
The big block Ford 390 is still a relatively popular performance engine platform, though it does have a few drawbacks. Aftermarket parts for Ford FE motors are widely available, but they tend to be quite costly. It would likely be about 1/3 cheaper to do the exact same build to a small block Windsor motors like a 302 or a 351.
Ford 390 Performance Builds
If cost isn’t the overriding factor, the Ford 390 is actually a great motor to choose for a performance build. There were a few legendary muscle car-era performance engines in the FE family, which means that the 390 has a lot of go-fast potential.
The most notable Ford FE-based performance engines are the 427, the 428, and the 428 Cobra Jet. It’s difficult to convert a standard Ford 390 into a 427 or a 428, but you can stroke it out and push respectable power with the right cam, heads, and a solid fuel and ignition system.
Adding a more radical camshaft and performance heads is another popular upgrade. Some people opt for a simple combination of long-tube headers and an RV cam for driveability, while others run through the whole top end.
For power, a stroker kit is definitely the way to go. A naturally-aspirated stroker can produce upwards of 500 horsepower, which stands a chance at smoking a Dodge Scat Pack with a 6.4-liter HEMI. People like strokers because they’re an attainable upgrade that can turn grandpa’s factory 1968 F100 into a street demon. And at the end of the day, it’s all still numbers-matching.
Ford 390 Problems
Like all engine families, the Ford FE 390 is plagued with a few design problems. Ford 390 owners commonly complain about bent pushrods and vacuum leaks around the intake manifold. But overall, these engines have a reputation for durability.
Valve cover leaks are common, as the covers sit on part of the intake manifold and the cylinder heads. This is especially common with aftermarket heads and intakes, as the height of the two surfaces sometimes don’t line up perfectly. If you use cork gaskets, you can solve this problem by carefully adding a bead of RTV to the affected area. Also, make sure that your valve covers aren’t bent or bashed too badly around the rims.
Ford 390 Reliability Upgrades
The newest original 390 rolled off the assembly line in the 1970s, meaning you’re likely to find a few parts that could use some modernization. Reliability upgrades are quick and affordable for this engine, and they can turn your 390 into a dependable daily driver.
Many people recommend installing electronic ignition. And while there are certainly benefits to electronic ignition, properly-adjusted ignition points can be just as reliable. If you have ignition points, replace all of the temperamental components. A new set of points and a condenser are cheap at any parts store, and the cap and rotor aren’t much more expensive. With just a few components, you’ve effectively installed a brand new ignition system.
Also, don’t forget to replace the ignition coil. This is especially important if you’re still running the factory coil and also if the bottom of the coil appears to bulge outward. Plugs and wires are the obvious next step, and they’re easy to come by as well.
Also, look for corroded or deformed wires and contacts, as these can be a nightmare down the road. Check the solenoid and the ballast resistor too, as these components can fail. Replace the belts and check the condition of the alternator. Most of these items are so inexpensive that you might as well upgrade them as soon as possible.
If you notice any cracked or fossilized lines, replace them too. Vacuum hoses and fuel lines can look acceptable, but you don’t know for sure until you give them a squeeze. If they’re hard as a rock, replace them.
The final system to check is the fuel system. Replace the fuel pump with a high-quality replacement, and make sure the lines and filter aren’t clogged. You can also rebuild the carburetor or replace it with a new one. Just make sure you find a carburetor that works with the factory linkage.
Ford 390 Big Block Resources
Vintage shop manuals are an excellent source for technical information and instructions. The Ford 390 is a temperamental motor, so having original sources can save you from a lot of headaches.
That said, the best place to get tips about the Ford 390 is from the guys who actually own them. Forums are extremely useful for troubleshooting these old motors, as the old-timers have spent years online documenting just about everything there is to know about Ford FE engines.
The most useful forums for the Ford 390 include Fordification, the Vintage Mustang Forum, the Ford FE Forum, the Ford Trucks Forum, and others. There are also several deep-dive Ford FE books available, such as Ford FE Engines: How to Rebuild by Barry Rabotnick.