Piston Slap: Putting the HO in Your Colony's 5.0!

Sajeev Mehta
by Sajeev Mehta

Joe writes:

Dear Sajeev,

It was a mild winter here in Minnesota, so it promises to be an early spring. And with spring comes the promise of new automotive projects. Right now we are in the pre-spring thinking and planning stages. Attached is a photo of my possible project. Some background would be helpful.

The car is a 1991 Mercury Colony Park. I purchased it in February of 2002 for the bargain price of $4,500. At the time it had 51,000 pampered miles. It had been rustproofed when new, and sat in a garage during every Minnesota winter. Not a hint of rust anywhere when I bought, and almost none at this time. It was purchased to pull a folding camper trailer. A $4,500 panther was a bargain compared to the cost of an SUV or other “modern” vehicle, and far more eye catching and unique. It ended up doing more than pulling a camper. It has been to Disney World 3 times, was displayed at Ford’s 2003 centennial celebration in Detroit, and has moved 2 kids off to college, along with countless camping trips and miscellaneous chores. As such, it has become a family heirloom and my wife and three daughters will not allow me to sell it.

It has 105,000 miles and remains quite stock except for the Keystone Klassics, some Bilstein shocks, and an aftermarket rear sway bar. Given its unique nature, and the fact that so few remain on the road in this type of exceptional condition, I want to keep the car looking and behaving as stock as possible, with the exception of the wheels and some more power. It needs some help under the hood. The stock 5.0 is what it is. The same basic engine could be found in a Mustang GT producing loads more fun. What would be your suggestion for extracting maximum fun from the basic platform that is here, while preserving the character of this final model year station wagon without spending boat loads of dollars and doing the work as a DIY project?

Despite my day job, I have very good mechanical skills. I have replaced head gaskets on a 3.8 litre 1993 Thunderbird, intakes on a 1996 Thunderbird, have completely refurbished the suspension, exhaust and external mechanicals on a 1979 Mazda RX-7 among many other projects.

It seems to me that a starting point would be cylinder heads and exhaust manifolds. What Mustang GT 5.0 litre bits will bolt onto the base 5.0? What about the engine control modules, something I have zero experience with, and what about transmission shift patterns.

Ultimately, I am looking for something that will never be raced, is not out to impress anyone but myself, but when I slide behind the wheel and put my foot into the throttle, it produces a kick in the backside like a 5.0 has the potential to provide.

Any thoughts on where to begin would be most helpful so that the spring planning session can get off the ground.

Regards,

Joe

Sajeev answers:

Thanks for your entertaining letter, Joe. And sorry for the delay in writing back, such is the way this Piston Slap thing works. But I love the Keystones on the Colony Park!

On the plus side, your query is very quick to answer. On the minus side, you’re making me feel very, very old. Because I (patting myself on the back) wrote one of the best 5.0HO (i.e. High Output) swap articles for Panthers. It didn’t feel like this article is 8 years old until I googled it… and formally present it to you all right here.

The “regular” 5.0 in the Panthers (and my favorite Fox bodies) are pretty sluggish by today’s standards. Plenty of off-the-line bump, and fuel economy better than most carb’d machines to boot. But converting to a 5.0HO from a 1987-93 Ford Mustang makes these 5.0s somewhat more appealing with no real downside. And, to your point, the HO swap is a period correct upgrade that anyone will appreciate. So just do it.

When the stock 5.0HO’s 225 horsepower isn’t cutting it, slap on a set of aftermarket aluminum heads (watch for piston to valve clearance) and the biggest 5.0 Whipplecharger kit you can find. It will make your Panther fast enough for damn near anyone.

For the record, I did the 5.0HO swap over ten years ago to the vehicle that’s currently my TTAC avatar: a 1988 Cougar XR-7. It’s still running strong. Ish. But everyone (and I mean everyone) loves the sound of this 5.0HO coming up the street. It will do…until I find a deal on those aforementioned heads and supercharger. Evil. Grin. ON!

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry.

Sajeev Mehta
Sajeev Mehta

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  • Chicagoland Chicagoland on Sep 06, 2012

    With the optional towing package, the wagons had trans cooler, HD radiator, and stiffer springs. Also 3.55 locked rear end! I had an 87 as project car, but had too much rust to restore. The trac-loc rear went through snow like nothing. The tow package was nearly same as PI package.

  • Acuraandy Acuraandy on Sep 06, 2012

    Being an ex-Malaise-era car 'modifier', some words of wisdom: leave the engine alone, concentrate on beefing up that AOD trans and rear end (must have an 8.8 or 9"?) for pulling around that pop-up trailer. There aren't many Panther wagons in such condition left that hadn't been overly molested/destroyed by my fellow Gen Why'ers who inherited these rides from parents/grandparents and wanted to cart their buddies around in a 'big Mustang'. Keep 'her stock other than that. From the former owner of a 3rd gen Camaro (and tried unsuccessfully to 'convert' it from a 305 pooch to a fire-breathing 350 (I think) unibody twisting monster), you'll thank yourself for not messing with it later on. Another thing to keep in mind; (an irony here in the 'state where nothing is allowed') Minnesota doesn't have emissions testing anymore (YET), but who knows how long that will last with impending EPA regs. Save yourself a headache later and concentrate on the rest of the powertrain and maybe throw some hi-flow exhaust (with hi-flow 'cats') on it? And yes, mid 80's emissions equipment is rather difficult to deal with, but trust me... That way when Johnny EPA comes around and tests it, you can still run it on the road.

  • CanadaCraig You can just imagine how quickly the tires are going to wear out on a 5,800 lbs AWD 2024 Dodge Charger.
  • Luke42 I tried FSD for a month in December 2022 on my Model Y and wasn’t impressed.The building-blocks were amazing but sum of the all of those amazing parts was about as useful as Honda Sensing in terms of reducing the driver’s workload.I have a list of fixes I need to see in Autopilot before I blow another $200 renting FSD. But I will try it for free for a month.I would love it if FSD v12 lived up to the hype and my mind were changed. But I have no reason to believe I might be wrong at this point, based on the reviews I’ve read so far. [shrug]. I’m sure I’ll have more to say about it once I get to test it.
  • FormerFF We bought three new and one used car last year, so we won't be visiting any showrooms this year unless a meteor hits one of them. Sorry to hear that Mini has terminated the manual transmission, a Mini could be a fun car to drive with a stick.It appears that 2025 is going to see a significant decrease in the number of models that can be had with a stick. The used car we bought is a Mk 7 GTI with a six speed manual, and my younger daughter and I are enjoying it quite a lot. We'll be hanging on to it for many years.
  • Oberkanone Where is the value here? Magna is assembling the vehicles. The IP is not novel. Just buy the IP at bankruptcy stage for next to nothing.
  • Jalop1991 what, no Turbo trim?
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