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hey guys i jus bought a 89 4 banger for a project and was wonderin how hard it would be to drop in a 351w. i kno its a common swap so i was jus wonderin if its a simple drop in of the engine. i kno th frame is goin to be beefed up for the added weight but wat else should be done

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Ok I am going to list all the main parts needed if you plan on running a 351windsor instead of your 302 or a 302 stroker. First off let's address the financial part of this. Yes it wll cost a little money, but the advantage of starting with a 351w versus a 302 or 302stroker are plentiful enough to warrant the extra cost. Also remember, if you want to be real cheap just take a day and go to the junk yard. You can get some od the needed items for a fraction of the cost. Just as an example, the power steering bracket would be 60 dollars or more at Ford, at a junkyard it would be 5-10 bucks max. Keep it in mind.

The 351W is a Windsor class engine. It is made on the same factory line as our beloved 5.0. However, the 351 posseses several qualities that make it a desirable block for an engine buildup. The advantages of using a 351W vs a 5.0 (302):

Obviously, you get an extra 49 cubic inches of displacement. As the saying goes, there is no replacement for displacement. Second, the webbing in the lower half of the block is thicker, making the block stronger. Third, the crank has bigger main and rods journals, making the cranks more durable than their 302 counterparts.

FACTS: What you need to know/consider when you swap a 351W into a Fox3 platform chassis:

The 351 block is very similar to the 302. That means that almost all parts swap between a 302 and a 351. This includes: Heads, cam, lifters, timing chain, timing chain cover, water pump, engine mounts, and all sorts of other stuff. The bellhousing bolt pattern is the same as a 302, so all trannies that bolt to a 302 will bolt to a 351. However, there are some differences in the 351 that necessitate new parts:

1) The oil pan is different. Motorsports carries one. You can also get an oil pan of of an early eighties LTD Crown Vic. If you go the junkyard route, remember you also need a oil pan pickup tube, and a special main bolt that the pickup attaches to. The FMS pan is a pretty good deal, and if you shop around, you can get one for under $100, which comes with the dipstick, bolt, and pickup tube.

2) The internal balance of a 351W is the same as pre-81 302's (28.2 oz). The 5.0 HO has a 50 oz. unbalance, which means you cannot use the flexplate/flywheel or the harmanic balancer off of an HO engine. You have to get the correct pieces from a dealer/junkyard.

3) The deck height is higher, which means you need a different intake, since the 351W intake is wider. A 5.0 Upper will bolt to a 351W lower.

4) Also, a higher deck height means that the accessory bracket will need to be replaced. FMS sells the new bracket for about $50.

5) The higher deck height means the headers sit up higher than in a 302 powered Mustang. A special set is required for a 351.

6) A 351W will in all likelyhood not clear the stock hood. You will need a cowl hood for your car. Or you can use dropped motor mounts. Google for these.

7) The distributor has a fatter shaft. You can obtain one from a 351W powered FI truck (if you are using FI) or any late 70's/early 80's car using the 351W and a Duraspark system if you are going to build a non-efi car.

Those are the major differences. As you can see, for about $1000 you can put a 351W in your Mustang. This is cheaper than a stroker, plus you wind up with a more reliable engine.

Tips: There are several things to look out for to ensure that your swap to a 351W is easier and more successful. They are as follows:

1) A high volume oil pump WILL NOT clear the FMS pan. If you want to run an HV pump, you must either modify the pan (which is what I did), or buy a Canton or similar pan, for many dollars more. The modifications just include cutting down the front drain bolt, and welding on a corner to the pan to clear the pump housing. It cost me $25 to get my pan welded.

2) Get new motor mounts. If your mounts are questionable already, the additional weight of the 351W will make them fail in a hurry. I recommend the 87-93 convertable mounts, which will work in any 79-93 Mustang.

Remember to junk yard and ebay some of these items. There are quite a few header companies that have readily available headers you can buy.

1986-1993 Ford Mustang How To’s:
351w Fuel Injection Swap
Nathan Moonen
aka Mighty Mouse

INTAKES: When doing a 351w swap into your late model Mustang it is mandatory that you use a different intake manifold. The 351w is wider from head to head than its 302 counterpart. Unlike its low deck brother the 5.0, the choices are pretty limited when it comes to intake manifolds:

1. F150/250 5.8 (351w) upper and lower - don’t even think about it - they don’t flow and it would be a feat of engineering to get it to work. NO, the 5.0 upper will not bolt up to the 5.8 lower.

2. Edelbrock 351w Truck lower and 5.0 Performer/RPM upper - this is pretty common, but you have to purchase the two separately as Edelbrock does not sell it as a kit - expect to pay over $600.00 retail.

3. Edelbrock Victor EFI - Very Nice Intake, but not for the faint of heart. Better have a cam and heads to match it, or it would be a pain to drive on the street. Retails for around $600.00

4. Trick Flow - they offer 3 different arrangements depending on the seriousness of the 351w - prices range from $550.00 - to near $700.00.

5. Professional Products - new on the market, more or less a Chinese Edelbrock RPM rip off. The good thing about them is they come bare or polished and range from 425.00 - 599.00 retail respectively, and flow just as well as the Edelbrock RPM.

6. GT-40 (aka Lightning and 95 Cobra R) 351w/5.8 Lower and any GT-40 style upper (Explorer, GT-40, Cobra, Cartech, Downs Ford etc). Ford does not make the 5.8 lower anymore - so you are at the mercy of the swappers for that piece. . .

5. You can also have a carbed intake such as the Victor JR modified to accept rails, injectors and throttle body. Reichard Racing does this for a decent price.

DISTRIBUTOR: If you are using an 86-93 wiring harness you can use a distributor for a 1987 Ford F150 with a 351w/5.8 liter engine. If you are using a 94/95 wiring harness - use a distributor for a 94 F150 with a 351w/5.8 liter engine. If you are running a roller cam, retro-fit or not, you may need to swap the drive gear on the Ford distributor. You can also use an aftermarket distributor such as MSD; but unless you are turning some pretty serious revs - don’t waste the money. The MSD buzz box doesn’t plug into the distributor in an EFI application - it goes to the coil - which by the way the stocker will work for - but I recommend an aftermarket piece for a 5.0.

Side Note: If you built your Windsor, chances are you used either a Ford Racing or ARP Oil Pump Drive Shaft with a high volume oil pump. If so, you will need to remove approximately ½" of the bottom of the stock EFI replacement distributor shaft in order for it to seat in the block. When Ford revised the 351w for EFI they added ½" to the distributor for unknown reasons. If you are using a standard oil pump driveshaft - you will not need this step. You can see the line on the stock EFI distributor where Ford changed the casting process. I used a sawzall to make the cut - then cleaned it up with a grinder and wire brush. Slid right in!

CAMSHAFT: Any cam for a 302 H.O. will work for your 351w. All pre 1994 351w’s came with a hydraulic flat tappet style cam, and you can not run a roller cam unless you make some changes. You can use an off the shelf 302 h.o. cam if you run Crane/Ford Racing hydraulic link bar lifters FMS - M-6500-S58. You can also get a custom grind “reduced base circle” camshaft and get your block machined to accept the stock 5.0 style lifters, spider and lifter retainers. I recommend ponying up cash for the link bar lifters - even if you are getting your engine overhauled.

FUEL RAILS: Whatever intake you choose you will need to replace/modify some fuel rails. Some swapers purchase aftermarket rails and braided line. Some (if not most) of us are on a budget, and budgets usually declare that we must reuse existing parts if at all possible to do so.

The stock fuel rails on the 86-95 Ford Mustang 5.0 cars are capable of supporting over 500 horsepower - and up till the 2005 season there was a certain NMRA racer who ran 9.70's with stock rails. In order to adapt these rails to the wider 351 you will need to lengthen the hose that connects the two in the front and the rear.

You will need:

1. 2' of 5/16" EFI (not standard) fuel line
2. 4 small EFI fuel line clamps
3. Razorblade (exacto knife, box cutter etc)

This is a pretty simple process. Start by removing the rails and injectors from the 5.0 lower intake. If you are changing injectors, remove them at this step - they simply pop out of their chrome retainer. Don’t even try using a plyers to twist the old flex line from the barbed metal line ends. The stock setup is a dual inlay hose setup that is really tight to the barbs. Use a razor blade to cut down the line and then twist it off. The rear line is longer - 11" was perfect for my Edelbrock intake - the front only used 8" of line - to be safe measure your own distance (remember, measure twice and cut once). Slip two clamps over one end and slip the rubber line onto the barbed metal line tighten the clamps on both ends - repeat at the front or back and your done.

INJECTORS: Your 5.0 came from the factory with orange top 19# injectors. While this size injector is fine for stock power levels on the 5.0 - a mere cam swap can bring you past the 19# threshold. Virtually any 351w will need a bigger injector (regardless if the EFI truck 351's came with 19# or not). In order to determine your proper injector size a simple formula can be used (and you thought your high school math classes were useless):

Horsepower (HP) ÷ number of injectors x BSFC ÷ Duty cycle = proper injector size

1. HP - When using this formula be realistic when determining your horsepower - two big of an injector can make you car run rich and boggy.

2. BSFC - non-assisted cars (no NOS or super/turbo-chargers etc) BSFC is usually .50. Power adder cars BSFC is usually .65.

3. Duty Cycle - injectors work there best at no more than 85% of their capacity.

Eg. My old 351w is non assisted and was “estimated” at 417 bhp so here is what I did:

417 ÷ 8 (= 52.125) x .50 (= 26.0625) ÷ .85 = 30.6

-so for my engine 30# injectors was pretty close to ideal. Holley says 30# injectors are good to 450hp (citing up to 90% is ok), Accel says 400 hp is the limit - you be the judge.

MASS AIR METER: If you are running speed density see my other article on how to convert to Mass Air. If you don’t know the difference, take a step back from your car and do more research! If you have Mass Air already, you are on the fast track to Windsor power, or you can run a Speed Density tuner or chip - do not try to run a 351w on the stock Speed Density system.

In Mass Air Meters you have the benefit of the 5.0 parts bin - as they are interchangeable. Once again - the size of the meter all depends on how serious your Windsor is. A good rule of thumb is buy the biggest meter your budget and your intake piping allows. C&L states that their 73mm mass air meters are good down to 10 second / 600 horsepower Mustangs and the 76mm units will support 9 second / 800 horsepower Mustangs - and both will fit the stock intake or common aftermarket cold air tubes. I have no reason to disagree with this as they are going to have a much better idea than me about that. Just make sure your meter is calibrated for your injectors.

FUEL PUMP: The formula for this is really pretty complex - and using a larger than necessary fuel pump will not hurt anything since the 5.0 uses a return style fuel system. I love my 255lph Walbro - you can’t see the name brand of the pump in the tank - and Walbro makes them for Ford, Holley, Edelbrock and others. Minor bolt on 351w’s could get away with 110 lph (stock 94-98 Mustang GT pump), but anything that has better heads and cam will require at least the 155lph pump - use your best guess.

BOLTING THE WINDSOR IN: Everything else is pretty straightforward. You can reuse your front cover, water pump, thermostat housing, engine mounts, clutch, accessories and alternator bracket. You must use a 351w specific:

1. A/C and/or power steering pump bracket (Trick Flow, March and Ford Racing);
2. Oil pan (Canton, Moroso and Ford Racing);
3. 28 oz Balancer/flywheel; and
4. Headers - there are a multitude of 351w swap headers out there. I personally use the big tube/3" collector MAC header and I love the fit and finish for the price. BBK, Hooker, Kooks, Ford Racing all make headers in shorty and long tube depending on the seriousness of your combo.

Not that this should be a concern, but the 351w uses a different oil pump, pump driveshaft and pickup.

Parts needed for 351W fox body swap
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