351W

Next up on our project list is a super cool 84 LTD Crown Vic unmarked State Patrol car. Its bone stock.   Looks, stops and handles (!) like a million bucks.       But is lacking the beans. And is too damn quiet. Thinking HCI, 3.27s or 3.55's and just the right exhaust.     Does the new intake need to be EGR? Carb need to have Ford specific kickdown? Cam recommendations?        Also slightly off topic. It has fixed bucket seats that must have been designed for the vertically challenged trooper. Any ideas on how to make them adjust a few inches further back?       

Before you pick a cam you need to decide what, if anything you're going to do with the gears.  My recollection from mine is that they're really tall.  Like 2 something.  I embraced that with mine and built an engine optimized for low RPM torque. 

You don't need an EGR.  You will need a kickdown but most aftermarket carbs have a version that works with a Ford Kickdown.

I kept the factory exhaust manifolds on mine because I drove it in Upstate NY winters which would have made headers consumables.  I installed turbo mufflers and 3" catless dual exhaust.  It had a nice quiet rumble unless you really got on it.  Under WOT the intake and exhaust were about the same volume inside the car.

I don't remember an issue with the seats but I'm only 5' 9".  My 6" 3" buddy drove the car quite a bit and I don't remember him having any issues either.

You don't need an EGR, but you want it.  Follow me on this.  EGR only operates at modest throttle.  It is closed at idle and WOT, so it doesn't affect power in the slightest bit.  It does help to reduce NOx greatly, and helps cruise MPG.  There are really no downsides to EGR except the infrequent failures.

The 351W is just honestly a tall-deck 5.0L so pretty much anything that makes a Mustang go faster will work on that 351.  Your head choices number in the tens of thousands.  Trick Flow is the easy button, but GT40 heads are the Vortecs of the Ford world.   They can be found on 2 million 5.0L Explorers in junkyards.

Figure out where you want to go and how you want to get there.  Drag strip?  Fun street?  Highway cruiser?  You're probably looking at heads, cam, intake, carb, gears, and exhaust no matter which route you're going.  Which ones you get will be determined by your goals.  The 80s were the era of low compression, low-flow heads, and teeny cams while trying to chase CAFE and EPA.  Everything in those cars went to the extreme wussy side.  Fortunately, parts are cheap and junkyard swappable.   You likely have an 8.8" rear since it's the police version, but possibly a 7.5".  Door sticker will give you an axle code which will tell you the original diff and ratio.  Usually a number is open diff and a letter is posi, but not always.  Real way to check is to just look at the code on the actual axle.

If it's a true P71, it should have a posi 3.23, but only investigation will tell.

Curtis73 (Forum Supporter) said:

You don't need an EGR, but you want it.  Follow me on this.  EGR only operates at modest throttle.  It is closed at idle and WOT, so it doesn't affect power in the slightest bit.  It does help to reduce NOx greatly, and helps cruise MPG.  There are really no downsides to EGR except the infrequent failures.

I wouldn't recommend eliminating EGR just to eliminate it but if you're looking at modifying an engine keeping it does have two downsides. 

One is that it adds another tuning variable.  The other is that it limits your intake and cylinder head choices. 

Curtis73 (Forum Supporter) said:

If it's a true P71, it should have a posi 3.23, but only investigation will tell.

My recollection on the rear ratio could be wrong.  They could have been 3.23.  That's still pretty tall. It was close to 30 years ago that I had that car.  I do know that mine was a genuine interceptor and it did not have a posi because I distinctly remember installing one, outdoors during a snow storm. 

APEowner said:

Curtis73 (Forum Supporter) said:

You don't need an EGR, but you want it.  Follow me on this.  EGR only operates at modest throttle.  It is closed at idle and WOT, so it doesn't affect power in the slightest bit.  It does help to reduce NOx greatly, and helps cruise MPG.  There are really no downsides to EGR except the infrequent failures.

I wouldn't recommend eliminating EGR just to eliminate it but if you're looking at modifying an engine keeping it does have two downsides. 

One is that it adds another tuning variable.  The other is that it limits your intake and cylinder head choices. 

Curtis73 (Forum Supporter) said:

If it's a true P71, it should have a posi 3.23, but only investigation will tell.

My recollection on the rear ratio could be wrong.  They could have been 3.23.  That's still pretty tall. It was close to 30 years ago that I had that car.  I do know that mine was a genuine interceptor and it did not have a posi because I distinctly remember installing one, outdoors during a snow storm. 

Yeah, come to think of it, there were plenty of aero P71s with an open diff.  Stands to reason that there would be plenty of boxes with an open diff as well.

I may just be used to tuning for EGR, but it's not that big a difference.  Super simple on Qjets and Thermoquads.

Does that have an AOD?  If so then the carburetor will not have a "Ford kickdown" (only comes into effect near WOT) but a TV cable.  The AOD uses the TV cable for ALL load inputs, not a vacuum modulator and kickdown linkage like the old 3 speeds.

Get the TV setup wrong and you can hurt the trans.  It used to be common for AODs to get burned up in as little as a few miles after the plastic bushing on the throttle arm fell off.

If it still has a C4 then disregard this   And if it has a C6, then whoa momma, nice going!

Pete. (l33t FS) said:

Does that have an AOD?  If so then the carburetor will not have a "Ford kickdown" (only comes into effect near WOT) but a TV cable.  The AOD uses the TV cable for ALL load inputs, not a vacuum modulator and kickdown linkage like the old 3 speeds.

Get the TV setup wrong and you can hurt the trans.  It used to be common for AODs to get burned up in as little as a few miles after the plastic bushing on the throttle arm fell off.

If it still has a C4 then disregard this   And if it has a C6, then whoa momma, nice going!

Quoted to emphasize.   

Does it have a variable venturi carb?  If so, first investment is a 4bbl intake and a 600 Holley.

Yup, we smoked the AOD. Had my son replace the no bueno VVT with a 2BBL and killed the trans in like 20 miles. Painful lesson learned.....Going to toss the 2bbl into the shredder and install a 600 as recommended.  So this is an earlier car than Brother Curtis is thinking about and has way more cool stuff than I thought possible.       I got the Marti report and am pretty sure that it has a 2.73, 8.8. Have not had much heart to mess with it since the trans... But am ready now.      Goal for the car is to increase the torques by a bunch. It needs to sound beefy and won't see RPM much above 5K. Will soon get a moderately increased stall for the newer AOD in order to vaporize tires as required.    What it does shockingly well is steer and go around corners. And stops better than it should.  The frame is stamped HD and it has beefy anti roll bars front and rear.       I was stunned to find one so completely un messed with and want to improve the bits that need it while respecting its heritage and originality. So basically it should look just as it does but have improved performance "under the covers" as Closeau would say.                     

Whoop.... thinking 3.55s would be appropriate.

In reply to SPG123 :

That maroon car looks like an ex-Minnesota highway patrol (fun fact, my uncle was one of the first MN highway patrolmen, way back in 1929.  He drove a Model A Ford.  )

When I had my 5.0L panther it was well known that you could install fox body mustang shorty headers and the h-pipe to gain a free flowing exhaust that was easy to find on the aftermarket or used.  My car sounded great with the "HO" swap, but it was still a slow tank.  I would imagine a set of headers for a 351W fox and h-pipe or x-pipe would help.

Front brakes from the 98-02 cars can also be adapted if I remember correctly.  Taking some width measurements on the rear ends of newer cars might net you an axle with the right gears that would bolt in and have discs.

Md. State Police. Was ordered through the Washington DC sales district . And definitely a brass or admin car.  Have learned that Minnesota cars were this color and that same era NY Detective cars may have been as well. This was an unusual color for Maryland and never appears to have had a light bar. Was purchased by a Firefighter when it retired from service. And I bought it from his son. I believe it to have just over 100k original miles. 

In reply to stuart in mn :

When men were men!

He had to be a badass. Wasn't like you could call for an assist on the radio back  then...

In reply to SPG123 :

He was a big tough guy.  

Model A heaters weren't so great in northern Minnesota winters, either.  

Wow, what a great find! Forgive me if I reminisce for a moment. 
 

My 79 LTD Landau. Drove it from my last year racing trotters in 86 to three years out of vet school in 2000. 
The P71 sway bars made a big difference. That was the last year for a C4 transmission, so it was sold with a 7.5 inch 2.26:1 rear end to try to eke out some mileage. 
 

The last of my three engines was a 40 over 302 with a holly 600, performer intake, competition cam 260H, roller rockers, ported E7 heads, headman shorties, high flow cats, H pipe, 3 chamber flow masters (of course), and 2 1/4 dual exhaust. 
 

I kept the stock rear end, and had the transmission built with a set of wide ratio gears, 17% lower first, 8% lower second, and 1:1 third. 3700 pounds empty with a quarter tank. 
 

All of that got the 0-60 time down to ten seconds flat on my stopwatch. It really needed a gear change, but I did a lot of road trips back then. 

One quick thought on the seats: I'm not totally clear what you're describing, but if you're thinking that they were specially modified by the Department then it might be productive to reach out to the relevant motor pool and ask about it. I can pretty much guarantee you'll find somebody who (1) is totally chuffed that you have one of their old cars in such great condition, and (2) either knows every detail of the mods himself or knows somebody who does.

Thats a really great color, and as these cars are getting older they are definitely getting prettier.  Remember if you intake or exhaust swap it its not straight 302 parts, the 351W is taller and wider so you need 351W parts, especially the lower intake.  You can use 302 headers but they will sit approx 1-1.5" higher in the chassis than they were intended to.

If it was mine, big dreams here...

Keep the 351W, rebuild it with a stroker crank to get a 383 or similar.  You are gonna want the torques.

Convert to an aftermarket multipoint EFI.  EFI is a must-have for a daily for me.  

Keep the AOD but have it built, mid-stall converter.  You still have a heavy car that you will want to street drive. 

Keep the lockup in the converted for highway MPG and nicer cruising.

Some reasonably deep gears that will keep it around 2500 RPM at 80 MPG

Reasonably muffled down dual 2.5" exhaust, X pipe, and of course 40 series (or 50 series) Flowmasters.  Turndowns, tucked up under the body, not straight out under the bumper.  Nothing sounds as good as a "5.0 with flows"

Rebarreld and widened steel wheels set up to use some nice 17" performance rubber.

Refresh the suspension, all new bushings, but keep it springs and nice shocks.  Its never gonna handle great so may as well have it be comfortable.

Or hell.  Just 3.5 Ecoboost swap it.  

If it were mine I'd keep it pretty simple.  GT40 heads which should get you around 9.2:1 (IIRC), mild cam... let's say 214/222 on a 112 LSA.  That lets you keep a factory stall and cold/street manners with a significant torque bump.  Also lets you keep your rear ratio for now.  Heck, if it's a 3.23, that's actually not a bad match for that cam.

Round it out with full length headers, duals, quiet mufflers/resonators like maybe a Dynomax or Summit kit.  As much as this build is begging for a Qjet, I don't know how much luck you'll have finding a spreadbore intake for a tall Windsor unless it's iron.  Edelbrock used to make them but I don't think they do anymore.  But for the street, a Qjet is the only answer.  Holley will make 1.458 more hp at the expense of cantankerous tuning and widely variable AFRs in the midrange.  Unless you're a master carb tuner, Holley will drive you nuts.  Long warmups, frustrating cruise ratios, sensitive to atmospheric changes.  Qjets are complex but they do all the atmospheric referencing for you.  I used to be able to set up a Qjet that rivaled EFI.  I had a 454 that ran exactly the same in L.A. at sea level and 95 degrees as it did in Denver at 12 degrees.  Qjet wins for accurate metering, MPG, and set-and-forget.  Too many people read carb shootouts in magazines and go for the Holley because "2 more hp" and fail to realize that their street car spends next to zero seconds at WOT and redline where the test was made.

With a 26" tall tire 3.55 rear gears and an AOD is around 2500 RPM doing 80.  I had to look up AOD gear ratios and I have to admit that they look pretty well picked (much better for car stuff than the 700-R4).  Pretty hard to argue with 3.55's at this point.

Dynomax Ultraflow SS or Hooker Aerochambers would be my muffler of choice for this.  Had Ultraflow's on a 5.0 Mustang with a cat'd x-pipe and it sounded really nice.  Polished tips existing under the bumper might look nice, like an LX Fox Mustang setup.  

I have *no experience with these at all* so *do not listen to me* but I think I'd go get an Edelbrock Performer 750cfm vacuum secondary carb for a 351W built for the street.