the front windshield on the driver’s side of the dashboard, or on the door sticker.
If you are looking at a complete donor car or are shopping for a used engine, the vehicle VIN sticker in the door tells you a lot about the engine and drivetrain. The 8th digit of the VIN is the engine, and on this 2010 Mustang it is an “H,” which is a 4.6 3V engine rated at 315 hp. The 10th digit tells the year of manufacture, here an “A,” which stands for 2010 (note the car build date noted in the upper left-hand corner is 09/09). The transmission is denoted under TR as “K,” which denotes a Tremec TR-3650 5-speed.
These charts list the engine codes for modular engines 1991–2015. The key is as follows: SOHC = single overhead camshaft; DOHC = dual overhead camshaft; 3V = three valves per cylinder; C/R = 2000 Cobra R; R/A = Mach I Ram Air; GT = Ford GT supercar; S/C = Supercharged; B = Boss; FF = Flex Fuel; R = Romeo engine plant; W = Windsor engine plant; E = Essex engine plant; RA = F150 Raptor; CNG = compressed natural gas; NGV = natural gas vehicle; LPV = liquid petroleum vehicle; GFP = gaseous fuel prep
This breakdown shows the year digit, which is in the 10th position of the VIN. Ford used a letter at the end of the 1990s, switched to numbers for the 2000s, and then back to the beginning of the alphabet for the next decade.
The sequence of engine codes for modular engines from 1991 to 2015 was not consistent with letters and numbers, and used the same designators in different years. In some cases, within the same year the code could be for either a 6-cylinder or a modular engine, depending on the vehicle. The horsepower ratings also varied over the course of the engine series build, so it is provided here as a range. Finally, a W-code engine in a Crown Victoria and a Ford F-150 may have come from the same plant (Romeo, Michigan), but have different components mounted on it, such as intake and exhaust manifolds.
The 10th digit designates the year the engine was manufactured. Because of the many running changes in the plants, this may be helpful to you and your engine builder when searching out performance or replacement parts if needed.
The next level of engine ID is the engine tag. The engine tag includes information on engine calibration, date of manufacture, and assembly plant. Ford’s method of identifying engines varied in style and location. Some of them are stickers, others ink. It is possible that they can be switched or fade over time, so the identification of an engine can become difficult. Here are some of the ways to identify an engine.
Ford used primarily vinyl stickers to denote its engines through the modular engine years. The calibration code 2G839AA denotes this engine as a 2003 Cobra supercharged engine. The build date is noted as August 13, 2002, and it was built at the Romeo Engine Plant (REP). This sticker is located on the passenger-side valvecover at the bottom middle of the cover. A similar sticker is located on the driver-side valvecover, but only has the engine calibration code, date of manufacture, and a large bar code.
Ford has stayed fairly consistent with the base specifications of these engines, with only a few custom setups.
Although at least a half dozen displacements exist for the modular engine, the base dimensions are one of the more constant parts of these engines. All the engines share the same bore spacing at 100 mm (3.937 inches), except for the 6.2 engine. The two standard block deck heights are the taller 5.4 and 6.8 V-10 at 256 mm (10.079 inches), and for all of the smaller engines, 227 mm (8.937 inches). The 5.8 was slightly shorter at 225.7 mm (10.0673 inches).
But there are variations within variations. The 6.2 Boss SOHC shares many of the engine features of a typical modular engine, but it has a wider bore spacing at 115 mm (4.53 inches) and a unique deck height at 239 mm (9.41 inches). This allows for bigger volumes than the standard modular engine platforms. The Triton 6.8 V-10 is dimensionally a 5.4 engine with two extra cylinders.
Ford has had dozens of blocks over the years, made either from aluminum or iron. Five plants have made blocks for the modular engine: Romeo, Windsor, Essex, Teksid (Italy), and Cleveland, which manufactured the Boss. Between these engines not much interchanges. Some high-performance builders favor certain blocks, but in general all the blocks are very good, strong pieces. What you have will probably work fine.
All modular engine cylinder heads are made from aluminum and come in three basic configurations: a single overhead cam (SOHC) with two valves per cylinder, an SOHC with three valves per cylinder (two intake, one exhaust), and a dual overhead cam (DOHC) with four valves per cylinder. Ford has changed the intake ports and exhaust configuration frequently through the years, making it difficult to swap cylinder heads on these engines. Ford made some improvements in 1999 and introduced the PI head, which stood for “Performance Improved,” not “Police Interceptor” as older engines were designated. Early heads are referred to as NPI or Non-Performance Improved. Early 4V heads had dual ports, which was changed to a single port in 1999. SOHC and Coyote engines have round exhaust ports, and Cobra and other 4V heads were oval.
All modular engine heads are made from aluminum. The oval exhaust port on this head identifies it as a pre-Coyote 4V DOHC head. Note the added chain to run the second cam, the center-mounted spark plug, and the use of cam followers and valve-lash adjusters.
Crankshafts come in 6-bolt and 8-bolt configurations. The 6-bolt crankshafts were made at the Windsor plant, and the 6- and 8-bolts cranks were used at Romeo. Some special crankshafts were made, such as the forged-steel crank first used in the 2003 supercharged Cobra engines. A lot of performance parts, such as flywheels and clutches, favor the 8-bolt crankshaft.
In 2016 Ford introduced the new flat plane crankshaft for the 5.2 Voodoo engine. The firing order is different from all the other modular engines and gives the engine a unique sound.
Ford turned the performance world on its head with the 2016 5.2 flat plane crankshaft. The flat plane crank allows the engine to fire left right bank evenly, different than normal V-8 engines. This allows for better exhaust scavenging than traditional V-8s. Weight savings is due to not having additional counterweights. Firing order on most modular engines is 1-5-4-8-6-3-7-2, and the 5.2 is 1-5-4-8-3-7-2-6. (Photo Courtesy Ford Performance Parts)
Valvecover
