351w Engine Swap

Breath new Life into your ’86-’95 Mustang


The 5.0 is an excellent engine and can be built up to give the stock 351w a run for it's money but there's no Replacement for Displacement! The 351w does offer a lot of "bang for your buck"  and is overall a stronger block than the 302.  It has more cubes  than you can affordably extract than from a 302-based "stroker" engine.

The Engine Swap

As swaps go, the 351W/Fox chassis swap is pretty simple, with very little modification . The good news is the stock motor mounts location are the same, as well as the front cover, the stock radiator , the shroud, the water pump, Transmission, bellhousing, the pulleys, and all of your accessories when the proper brackets are used .

The 351W also has a  different balance than the 5.0. Being that we provide the Harmonic Balancer and Flywheel this isn't an issue. The 351W requires a 28-inch/ounce unbalance, while the 5.0 uses 50-inch/ounce unbalance.

As mentioned earlier, the stock motor mounts will work. But, because the 351W is 3 inches taller than the 302 (measured from the bottom of the stock pan to the top of the stock valve covers, the 302 measures 203/4 inches, the 351W 233/4 inches) you could possibly encounter hood-clearance problems with fuel injection. The Carbureted setup will clear. There's an option to use solid motor mounts, which lower the 351W by 3/4 inch in the engine cradle, improving both hood clearance and center of gravity or a lower profile polyurethane mount past customers have used with success.  Fortunately you won't  encounter any clearance problems with the stock crossmember and rack down below as long as we provide the fox body 351 pan.

 You may still require a cowl hood if you’re beginning with a car that was originally equipped with a four-cylinder or V-6 engine, or you just want to use stock-type motor mounts,

Cylinder Heads and Intakes

 Because the 351W has taller decks than the 302, this places the cylinder heads further apart, we use a 351w  lower manifold and a high performance  upper 302 upper  intake plenum. 

Accessories and Exhaust System

Your stock 302 power-steering and air-conditioning (if  equipped) brackets will not work on the 351W, but  good news. Ford offers a 351W Engine Swap Accessory Drive Kit for the ’85-’93 Mustang that is available with the power-steering bracket only (M-8511-A351) or with both the power-steering and air-conditioning brackets (M-8511-B351). This can be purchased through Engine Factory as well.

Whatever exhaust system you currently have will work, but the headers you have (factory or headers) will not, again because the 351W is  taller. MAC, Hedman and among others offers short-tube 351W swap headers that will bolt up to the stock or stock configuration aftermarket H-pipe.

Fuel and Ignition

While the stock fuel system will sustain a stock 351W, our 400 HP / 351W will need more-so the fuel system will likely require some upgrades. Beginning at the fuel tank, replace the stock pump with a larger unit,  The 150lph is good for about 400-plus horsepower; the 190lph  is good for close to 500 HP using the stock lines and 351W rails.

A mildly built 351W can use 24-lb/hr injectors, but we use 30-lb/hr injectors . Whether you’re building a more normally aspirated engine or a serious supercharged engine, you’ll need a mass air meter calibrated for your new injector size, such as those 

Finally, we're using a later, roller-cam- equipped 351w engine (’94-up or retrofitted), and replace the cast-iron distributor gear with a steel gear.

Horse power: As popular as the 351W-in-a-Mustang swap is, Ford waited until the last year of the Mustang’s pushrod engine to offer a 351w. But only 250 units of the ’95 Mustang Cobra R were produced with the 351. That R’s engine produced 300 hp at 4,800 rpm and 365 lb-ft of torque at 3,750 rpm.  We have had customers call us claiming huge torque gains over the factory 5.0 litre engine.


Call 1-800-704-5385 for Pricing

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