Lame Ponies: The 6 Worst Mustang Engines Of All Time

The Ford Mustang is an American icon that exemplifies horsepower, speed and performance. But there have been some dark times under the hood of America’s favorite Pony car. While today’s snarling 5.0L Coyote powered Mustang is a modern thoroughbred, it wasn’t always this way. Presented below are six of the worst Mustang engines to grace the Mustang nameplate. 

1964.5–1965 Thriftpower 170 CID I-6

Straight out of the gate the Mustang was saddled with a lackluster engine. Plucked from the Ford parts bin the Thriftpower 170 inline six already powered the Falcon. Since the Mustang was from the same underpinning as the Falcon, it was an easy choice for Ford. But the Mustang was marketed as an exciting sporty car, something that the 101 horsepower six-banger didn’t exactly inspire. A Falcon sourced three-speed manual transmission didn’t do much to liven up the driving experience either. Ford soon bumped up the base engine to a 200 CID unit that made 120 horsepower, but anyone who drove an earlier model would have left the experience lacking.

1974–1978 2.3L Lima I-4

Fuel shortages put a world of hurt on performance engines in the 1970s. Manufacturer reactions ranged from desperately trying to make their big V8s more efficient, to simply using smaller engines. Ford was already looking at downsizing the Mustang, so when the Mustang II arrived in 1974 it had the 2.3L Lima 4-cylinder engine under the hood. Rated at a whopping 85 horsepower the little 4-cylinder sipped gas but could barely get out of its own way. Amazingly Ford kept massaging the little Lima’s formula over the next decade finally extracting 205 horsepower via a turbocharger in the Mustang SVO.

1974–1978 2.8L Cologne V6

As we said, the 1970s were a dark time for engine performance. Those who opted to move up the engine option list in the Mustang II were rewarded with a 2.8L V6. For 1974-75 buyers the little Cologne V6 was also the only other engine option; a V8 wouldn’t hit the order sheet until 1975. Ford actually shared the Cologne V6 with its European production lines where it powered the Mercury Capri and others. Unfortunately the little V6 only made 105 horsepower in 1974 and actually lost power by 1978 being rated at only 90 horsepower. 

1979 5.0L Windsor V8

You would have thought that bringing the 302 back would have been an exciting time for the Mustang. Now dubbed the “5.0L” thanks to engines adopting metric displacement measurements, Ford hoped to rekindle their famous engine flame. The Fox-body platform was a new exciting look for the Mustang. Sadly that excitement evaporated once the driver realized there was only 140 horsepower under the hood. At least the torque output came in at 250 lb/ft, so the larger displacement did help. Buyers would have to wait until 1982 for the 5.0L to return with a more respectable 175 horsepower.

1979-1982 Thriftpower 200 CID I-6

It’s back! For the rest of Ford’s product line the trusty Thriftpower inline-6 never really left. But for some reason Ford decided to launch the new Fox body platform with an absolute dinosaur of an engine. It wasn’t totally their fault though. Turns out the 2.8L Cologne V6 was in short supply so a substitution had to be made part way through 1979. Ford dug into the parts bin and came up with the trusty, yet uninspiring 3.3L inline-6. Now putting out a raucous 89 horsepower Mustang owners could boast of sharing an engine with their grandpa’s pickup.

1980–1981 4.2L Windsor V8

With the dark days of the 1970s in the rearview mirror, it was time for Ford to unleash a new V8 engine to Mustang buyers. Sadly that engine was a 4.2L (255 CID) Windsor V8 created by neutering a 302 block. Driven by constricting EPA standards while also trying to appease Mustang buyers, the need for a V8 of some kind of high. The result was technically a V8…that put out a dismal 115 horsepower. Truly a low point for Mustang V8 performance. 

Some Perspective

It’s easy to look back and laugh now considering even the current base model 2.3L EcoBoost turbo Mustang makes over 300 horsepower. Of course even a modern Camry packs 225 horsepower, so things to get better over time. Some of these worst Mustang engines have their fans and that is okay. There were also constraints of the time that required Ford to get creative with their engine lines. Ford wasn’t alone either, both GM and Chrysler had their own disappointing engine offerings. Just because one of these engines powers a Mustang doesn’t make it necessarily bad, but it definitely could have been better.