By on September 6, 2012


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.



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 [email protected] Spare no details and ask for a speedy resolution if you’re in a hurry.

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41 Comments on “Piston Slap: Putting the HO in your Colony’s 5.0!...”

  • avatar

    That’s one pretty panther.

  • avatar

    That car brings back memories to me, but in country squire form. I think back in the early 90s my dad might have been inclined to attempt that swap had he known about it.

  • avatar

    Beautiful ride!

  • avatar

    Wouldn’t it just be easier to search for a decent used 5.0 HO, or even a crate motor, than attempting to mod/upgrade a vanilla 5.0 to near-HO spec?

    For that matter, how about just slapping a nitrous kit on the old 5.0?

  • avatar
    Polar Bear

    Is 4,500 dollars for a 20 year old Mercury a bargain?

    • 0 avatar

      With 50,000 miles and in beautiful shape? You have to be kidding.

      Yes – for an enthusiast appreciative of the vehicle’s historic character and exclusivity. Or for anyone yearing for a reliable V-8 cruiser with a ton of utility.

      No – to anyon that prefers their Corolla/Toaster/Hybrid as they don’t have to worry about it and like that their garage/drive way tool kit includes lawn darts and matching koozies rather than wrenches/grinder/impact wrench/pair of balls.

      Now, if you just prefer the Chevy small block to the Windsor V-8, or the Caprice Wagon that’s completely understandable.

    • 0 avatar

      I think your math is off a bit and like most articles I’ve seen you comment, you’ve failed to read this one comprehensively.

      He bought it in 2002 for $4500, it would have been 11 years old then. That is one hell of a deal!

    • 0 avatar

      Nope, I regularly found low mileage Panthers on craigslist for $1000-$2000 during my hunt, the problem was finding one that had been maintained decently.

  • avatar

    Your engine is good so I’d leave it alone. A $1K axle-ratio swap, to say 3.73s, would wake it up and give you the best bang for your buck. You’d be amazed at the power that’s unleashed without any real penalty at the pump. It’ll turn a bit more rpms on the hwy, but a few less around town. Then you can go more aggressive on its timing.

    A $2K STS catback (single turbo) would be a sweet upgrade. It just hangs in place of the muffler plus you can skip the blow-off valve and intercooler because it’s an automatic and you’re not going racing.

    • 0 avatar

      I have a ’95 Cobra with the last 5.0L. Parts are insanely easy to find for the 302 V-8. For this, if you don’t want to spend a lot of money (cheapest supercharger I can find is $3500 from Jegs), you can get a lot without too much money.

      An 85mm throttle body, MSD ignition coil, Cold-Air intake, Ford Racing 9mm wires, Ford Racing distributor with cap and rotor, and cat back exhaust should net you some decent HP gains and sweeten the response of the 5.0L.

      • 0 avatar

        What ring & pinion are you running? My ’90 rag top was a slug by ’00 standards so I ditched its 3.08s for 3.73s and that turned it into a real animal!

        The 3.08s spread the gears apart and I was always hunting for right gear around town. At 55 mph, I had to keep it in 4th (and 2K rpm) to not bog the engine. That or drive 65 mph (in 5th) in a 55 zone. Getting into overdrive sooner means zero penalty at the pump because I mostly drive it around 55 mph or less.

        The engine makes sweeter sounds too because it revs quicker and doesn’t sound bogged, and it was. The 3.73s turned it into an overall better car and much better drive. World class almost.

    • 0 avatar

      3.73s on a motor that’s completely out of breath at 4500rpm is a little pointless to me. E6 heads and a 50mm throttlebody are just terrifyingly bad, I think a 5.0HO (or an engine swap) is mandatory for any hot rod box Panther.

      • 0 avatar

        I don’t think so because it’s not working nearly as hard to do the same work. It really lightens the load and you actually feel like you lost half of its curb weight.

      • 0 avatar

        Well yes and no. This vehicle is used on the highway a lot(?), and gears might be a total killjoy for the owner. Plus, with only 3rd gear available at full throttle, it’s a little hard to go anywhere with a powerband this horrid.

      • 0 avatar

        Automatic overdrives take a bigger cut than manuals plus lock-up. It’s a mathematical equation and it sounds like he’s willing to give something up at the top for better all around performance. Never mind the costs, head aches and downtime of diving into deep into engine or a conversions/swap.

        I know what I would do, and it comes from experience. I had no idea what a gear swap could do for a V8 with factory and highly economical gears. My trans builder buddy had a set of 4.10 gears (and posi) that would go right into my ’79 Mustang and I just had to give up my aquarium (that he wanted).

        It went from barely keeping up with new CRXs (at the time) to dusting anything that crossed its path. The difference was ridiculous. I went from barely being able to chirp one TRX off the line to getting sideways in 2nd gear.

        The problem was it lacked overdrive. I settled on 3.54s, but with overdrive and lock-up, it would’ve been game on!

      • 0 avatar

        Good points. Honestly, gears and a less horrible motor are both on my mind. I’d just want the motor first, having spent too much time with 5.0 SLOs.

  • avatar

    I did a 350TPI swap into an ’89 Caprice back in 1996, using the Helm shop manual for the Caprice, the Helm manual for the donor car (’87 Firebird Formula 350)and JTR’s “Chevrolet TPI/TBI Engine Swapping” book.

    Speaking with author Mike Knell one day, picking his brain about some electrical issue while the swap was underway, he gave me the best advice you could ever ask for in performing this kind of engine change:

    “Make the engine think it’s in the vehicle it came out of”.

    Made the rest of the project go much more smoothly. I drove that swap for 137,000 miles before the tranny died and the rust monster came calling.

  • avatar

    In 1990 I had the good fortune as a college senior to hang around Milford Proving Grounds for a couple weeks; I was working on the NVH package for the stock Corvette. Pretty heady stuff at 22, but also showed me how plodding and inwardly focused the General was… I made my decision to avoid the OEMs and work for a supplier because of it.

    Anyhoo, they had a chase wagon for the ZR1 development crew with tires and instrumentation in the back. It was a Buick Roadmaster with ‘wood’ panels… with the Corvette dash, seats, steering wheel and suppposedly a ZR1 motor in the bay!

    I can’t remember if it had suspension mods too (probably vital) but just checking out the interior was a hoot.

    Now if you could get a diesel and a 6 speed in it they’d sell, right?

  • avatar

    The stock EFI 5.0 in non-HO form was a bit of a slug, especially in a heavy vehicle. My F-150 4×4 really struggled in the mountains with 185hp and 3.54 gears. I suspect that wagon has 3.08. I agree with looking into an axle ratio swap first.

  • avatar

    A quick search popped up a/mass air meter for the big merc, so why constrain yourself to a short deck Windsor. In the 80’s the wagon was fitted with a 351 so there is ample room for the swap. A tall deck Windsor can be had in a variety of displacements ( I think the largest I’ve seen is 460 but I suppose some crazy fool has made something bigger) if a person is willing to do so.

    As a towing motor a big cube Windsor with a small set of good flowing heads ( say a 408 fitted with a set of AFR’s 165cc heads) and a nice longer runner intake ( Edelbrock’s performer efi manifold) along with a nice can ground for off idle performance would make a nice combo.

    Years ago Jim Fueling ( anybody remember that awesome guy – R.I.P) was working on a set of heads for big block Chevrolet using insanely small valves, chamber volumes and port volumes with a super high port velocity with high compression ( well static anyway) to achieve incredible torque numbers ( the article at the time suggested diesel like performance from a gasoline engine). Anyways I digress.

  • avatar

    Great article link, Sajeev. If he wants to keep the short block, I would find a set of E7TE heads off Craigslist, have them ported with a 3 angle valve job, and add a set of tubular headers. Cheap fun.

    With the HO block in my ’93 notchback, I am very happy (for the moment)with ported, polished and port matched E7TE heads with GT40 springs and valves, a GT40 intake, the stock HO cam, and 1.72 roller rockers.

    • 0 avatar

      Just you wait until you go AFR/TFS heads. Just you wait…

      And, times have changed: I wouldn’t spend a dime on machine work for used E7s, when far better heads (GT-40) can easily be had for the same price, or less!

    • 0 avatar

      I’ve been down the modded E7TE cylinder head road before – had a set and worked them over completely ( ported all the way from the intake port to the chamber to the end of the exhuast port, converted to an adjustable valve train, big valves) I don’t think the flowed much better than an out of the box set of world products Windsor junior heads. The cost back then to do the heads was about 1200 bucks. I would have been money ahead at the time just buying a set of good aftermarket heads.

      If the GT40P heads didn’t have such a pain in the arse exhaust port location and a non- adj valvetrain , I’d say go for a set of those then again if you can score an entire motor from a first Gen Lightning, that’d be a good way to go as well (GT40 heads, cool tubular intake, 351 cubes) just need to convert to a roller valvetrain and freshen things up.

  • avatar

    Forget the engine, strengthen the transmission first so it’ll handle the extra power later down the road.

    It’ll also keep your transmission from breaking, that wagon is around the sinister 100k mark where most Panthers seem to toss their transmissions.

  • avatar

    Not that I think he would go this way, but for the cost of a 5.0HO and a supercharger, he could probably swap in a Coyote 5.0. With a little suspension and brake work that could be one heck of a sleeper!

  • avatar

    Sky’s the limit with a 5.0. Forget about swapping in an HO engine or bits. Aftermarket parts will kick the snot out of anything you’ll find on an old HO. Parts are not quite as plentiful or cheap as small Chevy stuff, but damn near.

    I would start small. Pull the heads and have them gone through (3 angle valve job, gasket match and port/polish, etc. . .). Won’t cost you an arm and a leg, and will probably net the largest gains for you down the road. Good heads make or break the deal.

    Tack on a larger throttle body and bigger injectors down the road (maybe an intake???). Racing wires and caps are a waste of money, IMHO. That factory ignition should be throwing plenty of voltage. As long as the plugs and wires are fresh.

    PS: Those keystones are SWEET on that car.

  • avatar

    Three words: Griswold Family Truckster!!

  • avatar

    cool camping car. that is the old school version of a ford flex, which, i can tell you, provides loads of room and pulling power for a pop-up camper. nice alternative

  • avatar

    I like wagons.

    I love old wagons.

    I lust for your old wagon. I expect you can get out of this pretty inexpensively if you watch and peruse the junk yards. I think I would make sure the transmission and gearing are good because they are cheaper to fix before they break. Gearing and breathing unlock the 302.

  • avatar

    The 302 has decent flowing heads but a port and polish certainly wouldn’t hurt along with a cam that makes power at lower RPMs since the car is used for towing and hauling heavy loads. Add headers, a Bassani X or Y pipe, high flow cat and muffler and you should see decent gains without drastically altering the car’s originality. If this isn’t enough I’d go for a regear as some of the other posters have mentioned.

    Once you start getting into forced induction or motor swaps your transmission (AOD presumably) becomes the weak link without beefing up the internals. I would install a transmission cooler if you don’t already have one no matter what you decide to do.

    You might also try what’s called the “Sixliter” tuneup to gain a little extra power and fuel economy on the cheap. It involves upgrading your coil, plug wires, increasing spark plug gap and bumping the timing. Specific instructions are easy to find with a quick Google search.

    • 0 avatar

      A “sixliter tune up” won’t do squat on a 5.0. The stock coil is good for 400hp to the wheels, and I have a dyno sheet to prove it.

      Bumping the timing is a good idea, though I’ve heard that sometimes EEC-IV will retard the timing in response. Not exactly sure why some people had that problem.

      The 5.0HO is almost perfectly optimized as-is. Add an intake or any other piecemeal modification and you just piss your money away. Go big or don’t bother.

      The 5.0SLO, on the other hand, just needs to go away. The only thing valuable on it is the short block, even if it has flat-top pistons.

      • 0 avatar

        I’ve had good luck with the sixliter tuneup on my 5.0 Bronco, nothing drastic but certainly the butt dyno noticed a difference vs same components with stock plug gap and 10 degrees base timing.

  • avatar

    Love it. I really have a soft spot in my heart for these “woodie” wagons – they’re American classics and much cooler than any appliance like a Camry or a Civic could ever hope to be.

    I’m sure you’d be more than happy with a stock 5.0L H.O. swap. Gears aren’t a bad idea, but 3.73s might be a bit much and cut into highway fuel economy. A nice compromise might be 3.55s.

    I love “woodies” so much that I hope the upcoming Grand Wagoneer that Sergio has hinted about has optional woodgrain available – if not from the factory, then at least as an accessory through Mopar.

  • avatar

    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.

  • avatar

    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.

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