The EVOS concept.

Details of the 2015 S550 platform Mustang are one of the most closely guarded secrets in the automotive world today. We prowl the internet everyday hoping to glean more information. Occasionally we find something that appears credible, but most of the time we find renderings and suspect speculation, which we must then debate on whether to bring to you here.

The latest, and strongest rumor we’ve heard in a while is a hot one though. A supposed Ford insider has recently leaked the engine lineup for the upcoming Mustang. The rumor is that Ford has planned a three engine line up.

Three To Go

We’ve known for at least two months that an EcoBoost four-cylinder would be an optional engine for 2015.

According to a supposed Ford insider, the engine lineup starts with a 2.5L EcoBoost four-cylinder mill that the source says produces 300 hp, this could be either the base engine, or perhaps the power behind a new SVO model. As a base engine it could be a volume seller, especially for rental car companies, and those less interested in all-out performance. It would also help Ford meet the CAFE requirements that threaten to wipe V8 musclecars from dealer showrooms all together.

The next rumored engine is a 3.7L V6, the rumor with this one is that power output could be as low as 305 hp, as basically a carry over from the current model. Alternatively the same source says that it could be the 3.5L EcoBoost model taken from the F150/SHO and pumped up to 400 hp.

Rumors have circulated that the EcoBoost V6 would not fit in the Mustang chassis for packaging reasons. However, given that this same engine is packaged for both the truck line, and the passenger car line, we would wager that given the importance of the Mustang platform, engineering the packaging for it to fit the new S550 Mustang will not be a problem if Ford really wants it in the car. Consider that the current Coyote is only one-inch smaller in width than the famous BOSS 429 of the late 1960’s, we don’t see how a fitting a twin turbo V6 should be any issue if a BOSS-Nine in theory would fit in there too.

Why couldn’t the EcoBoost 3.5 be packaged to make 400 hp and fit the S550 chassis?

While the original SVO was a four-cylinder, and some purists will cringe at this idea, it might also make for a better performance package to slap the SVO name on an EcoBoost V6. The original SVO rivaled the pushrod 5.0 for OEM power output, this would seem to us to be carrying that same theme. It would also give the Mustang a healthy engine option in the European market to compete with many other coupes that it will likely be battling. An EcoBoost four-cylinder would require repackaging to fit a rear wheel drive platform anyway, so why not the same for an EcoBoost V6?


The final rumored engine according to the source would be a slightly revised 5.0 Coyote. Firing yet another salvo in the ponycar wars, the S550 Mustang GT would be carrying a big stick and running a 475 hp version of the popular 302. It’s hard to say exactly how Ford will achieve 475 hp. We would speculate the use of direct injection would help with this since the cylinder heads are already cast with direct injection in mind. Adding DI could allow for more power in the form of either a higher compression ratio, or more aggressive cam profiles, and timing. It may also open the door to further improvements in intake manifold design, and even a cylinder shut down system for cruising, improving fuel economy and emissions while allowing for V8 power on demand. No doubt the engineers have found a way to boost power and ensure the 2015 Mustang debuts as king-of-the-muscelcar-hill.

Rejoice V8 fans, the Coyote stays, and likely is getting a 50-plus horsepower bump.


In the styling department the insider is said to have stated that the Mustang will have strong European influence in it’s lines. This would tend to confirm speculation that we’ve seen and brought to you here for the past several months. We suspect that the new Mustang will be very EVOS looking, while retaining some signature Mustang cues, such as the traditional long-hood, short deck design, small rear windows, some sort of side scoop that has been consistently present on the car now for the last 20 years, along with a large grill, obviously featuring the running horse badge.

With the Mustang also heading to Europe it must evolve, and go away from the retro-party that has dominated much of the car market for over a dozen years. Sales have slowed domestically the last couple of years, likely signaling that buyers are ready for something new.


No one outside of the design team knows the exact styling yet, but the Mustang must appeal to a broader market than ever before.

According to the AmericanMuscle Blog where we found this information, the source for the rumors is a Michigan resident, even posting proof of address on the forum where he laid out these details. He received this information from an acquaintance who is supposedly working on the 2015 Mustang project. This coupled with the fact that many of his claims back up some of the other rumors we’ve reported on in the past add at least some level of credibility to the information he provides.

If these rumors regarding the engine lineup are true, we’d have to say that the base through GT model Mustangs will likely have the best engine lineup in the car’s history.

Only time will tell if these rumors and our own speculation are true or if they’re simply someone else ringing their own bell, but as we find them, we’ll continue to bring them to you.