Ultimate Performance or Total Dealbreaker? Why the Fox Body Mustang Might be the Worst Car for an LS Swap

• December 4, 2023
• Story By
  Mike Garrett

Though you don’t see it nearly as much these days, the Chevrolet vs Ford rivalry among car enthusiasts is one of America’s oldest traditions.

The Calvin stickers. The jokes. The racing grudge matches. The intense loyalty that many Chevy and Ford fans had toward their preferred automaker was not to be taken lightly.

And to many of these enthusiasts, putting a Chevy engine into a Ford (or vice versa) has long been considered nothing short of sacrilegious.

Unwritten Rules?

Today though, with builders getting ever more ambitious and rule-breaking with their projects and LS V8s being swapped into every type of vehicle under the sun, those old brand allegiances aren’t as prevalent as they used to be.

There is one LS swap candidate though, which despite making great sense on paper, I just can’t quite get behind. And that’s the Fox Body Ford Mustang.

Now there are lots of reasons why the LS into Fox Body swap makes logistical sense. The LS V8 is compact, inexpensive and has near limitless power potential and aftermarket options.

The Fox Body Mustang is light, has plenty of space in the engine bay and has a massive aftermarket allowing the car to be setup for any type of driving you may want to do.

On paper, it’s hard to argue with the combination. But if you look at it a little deeper, a Fox Body Mustang might actually be one of the worst candidates for an LS swap.

Dollars and Sense

Now I’m far from an automotive purist. And my reasoning for this doesn’t come from a place of Ford brand loyalty, nor putting the Fox Body Mustang on a pedestal as a perfect car, not to be messed with. It’s simply that the juice isn’t worth the squeeze.

For starters, a Fox Body Mustang isn’t the budget platform it was 10 or 20 years ago. A decent Fox Body chassis is both harder to find and more expensive than ever. And right away that takes away most of “budget” appeal of a Fox Body LS swap.

In another time when you could find a non-running, complete Fox Body for $600, the LS might be the smartest choice for street and track performance — but those days are long gone.

Second, the Fox Body already comes with its own small block, overhead valve V8 that has some pretty incredible power potential of its own.

In fact, the performance and capability of the fuel-injected 5.0 HO engine is what the made the Fox Body such a popular car in the first place.

It’s one thing to pull out a four-cylinder or V6 engine, or even an ancient carbureted V8 for an LS, but putting a GM V8 into a Fox Body isn’t going to fundamentally improve the nature of the car.

If you are going to go through the effort of LS swapping non-GM car, why not choose something where an LS dramatically transforms the car?

Additionally, there’s nothing especially unique or interesting about an LS-swapped Fox Body. People already expect a Fox Body to have a V8 and be fast. It won’t be a sleeper, it won’t surprise many onlookers with a unique sound or an engine bay that makes someone do a double take.

Trust in the 5.0

Finally, with the Fox Body getting ever more rare, expensive and desirable among collectors, no matter how much money you invest, an example with a Chevy engine is most likely going to be worth less than one with its original engine — or a modern Ford V8.

Maybe you love the Fox Body Mustang but love the power and options of an LS V8? But it isn’t a little contradictory to love the Fox Body so much that you want to invest a bunch of effort swapping in a Chevy V8? 

If you want the looks and style an ’80s machine with LS power, why not a third-gen Camaro or Firebird - or a C4 Corvette where an LS swap would be absolutely worth the effort, while staying true to the roots of the car?

For serious racers chasing speed over everything, an LS might indeed have greater power potential than the Ford small block that put the Fox Body on the map - but is the performance gain worth the effort?

I think now more than ever, the answer to that question is “no”.