The Ford 400 is a beefed-up version of the Ford 351M (351 Modified). It uses the same bell housing pattern as the 429 block, which is also the same as the 460 block. Several changes to the 351M, including using a different harmonic balancer and flexplate, make a 351M into a 400.
What are the specs of the Ford 400 engine?
The 400’s main journal diameter was increased by 0.25-inch so that it could have more bearing surface area. The journal diameter at its increased width of 3.00 inches is the same as the 351W block.
Ford increased the crank stroke to 4.00 inches from 3.50 inches and increased the deck height from 9.206 inches to 10.297 inches. The increased deck height was required to accommodate the larger stroke.
Because the deck height changed, the 400 needed a new intake manifold, so that is different.
History of the Ford 400 Engine
The Ford 400 was introduced along with the 351 Modified in 1971. The 400 was used in many applications over the years. The 400 replaced the Ford 390, and it was designed for good acceleration for medium to heavy vehicles.
The 400 is basically a stroked 351– it had the longest stroke in pushrod engines at the time. The bore and stroke were each 4.0 inches. The low-performance 400 was designed for torque, thus, the reason the torque curve starts so early.
Because the 400 was designed to be a torquey workhorse, it didn’t make a lot of horsepower. In 1972, Ford changed to dished pistons, thereby dropping the compression ratio. Ford lowered the compression soon again, in 1973, plus changed the timing to 6 degrees, in an effort to reduce emissions.
In 1973, Ford again reduced the compression by retarding the timing to 6 degrees in an effort to reduce emissions. Over the next couple of years, the engine went through more changes, further reducing horsepower and torque.
With a lot of changes, the engine had problems with deck height and compression, which led to detonation. Keith Black made a piston to increase the compression ratio, which converted it to a “zero deck” deck clearance, but the Ford 400 never lived down its reputation for detonation.
Which Models Feature the Ford 400 Engine?
The Ford 400 was featured in the following models:
- Ford Custom, Galaxie, and LTD in 1971
- Mercury Monterey, Marquis, and Brougham in 1971
- Ford Torino and Mercury Montego in 1972 through 1979
- Ford Thunderbird, Ford F-series pickups, Lincoln Continental, and the Lincoln Mark V in the late 1970s
People Also Ask These Questions Related to the Ford 400 Engine
Is the Ford 400 a good engine?
If you keep the Ford 400 maintained, it will last as long as any other engine – upwards of 200,000 miles – until you have to rebuild it.
What is the difference between a 400 and a 351C?
The Ford 400 is based on the 351M. It was bored and stroked to provide more acceleration for medium- to heavy-weight vehicles. The 400 was lighter than the FE V-8 engines and the 385 series of engines.
The 351M debuted in 1975 once the 351C (Cleveland) had been discontinued. While you could say the 400 was based on the 351C, it was actually based on the 351M.
The 400 had taller pistons and a shorter stroke than the 351M.
How do I identify a Ford 400 engine?
Most of the Ford 400s have a bigger bell housing pattern, much like the 429. However, the only way to tell for sure is to remove the oil pan and check the casting numbers on the crank. Look for them on the side of the first counterweight.
A 400 crank is identified with the 5M, 5MA, or 5MAB casting code.
