The Mustang 5.0L Engine - S197 vs S550

While the 11-14 model Mustangs all received a very similar 5.0 engine, there are minor differences that set them apart. One of the main changes was the removal of the oil cooling jets which led to the 8HP increase. In addition to the removal of them, the pistons were slightly modified. They have the same cast but it comes with four extra oilers in the oil ring groove as well as a gas groove on the top ring. The block of the 13-14 models are also different than the preceding years. The head bolts were modified to be slightly smaller. As a result it received a different part number than the 11-12 years.

The 2015 Mustang took an already great engine and made some changes to make it even better. It took certain cues from the 2012-2013 Boss 302, but not all of them. It upgraded to Boss 302 forged connecting rods, but retains the pistons from the previous GT models. The only difference in the pistons is the notching for valve clearance from larger valves. As a result of the rod/piston changes, the crankshaft is rebalanced.

The 2015 GT also takes slightly from the Boss 302 heads. It uses a cast version rather than a CDC version of the head. This allows for the benefits of the head to be used on the 2015, but keep cost down to a minimal level. These changes also rendered a slight change in camshaft selection, with the intake giving more lift than a Boss 302 cam and the exhaust cam having the same lift as the Boss 302 (13mm). As a result of the camshaft change, valve springs are also changed to proper accordance. Timing is also modified slightly as well with a mid-lock system on the intake camshaft.

Having a different hood clearance and slight design changes, the 2015 5.0 also has a different intake manifold. The major change is the new manifold utilizes the charge motion control valves (CMCV) like older 4.6 engines. However, they have been designed to where they turn from the end, rather than the center like older models. As a result, they are completely flat against the runner when at full throttle, thus limiting the turbulence and airflow disruption.

The main things that set the 15-18 years from the 11-14 years can be summarized:

• Boss 302 connecting rods
• Cast version of Boss 302 heads
• Reintroduction of CMCVs in the intake manifold
• Camshafts

For most owners who aren’t looking to heavily modify the car, the changes are minimal and shouldn’t affect how you modify it. However, if one is looking to supercharge their Mustang, the resulting upgrades can allow the 2015 5.0s to hold around 800-850 RWHP safely. On the other hand, the 11-14 models are limited to 650 RWHP in stock form. However, both cars can be upgraded internally to hold even more power.

Although the engines are generally the same, there are differences in the wiring harnesses for the engine. As a result, if you wanted to swap a 15-18 5.0 into an older model, you must get the 15-18 specific control harness.

The GT350 is a direct showing of a constant improving in technology and performance. Using a flat plane crank rather than a 5.0 cross plane crank, the car can rev faster throughout the rpm range. It also has a larger bore size than the traditional 5.0, making it 5.2 liters. Being that the engine is designed to be naturally aspirated and not supercharged or turbocharged, it has a compression ratio of 12.5:1 (the coyote 5.0 has 11:1) It has different heads, camshafts, and intake as a result of these changes.