​Using a 351W in your Fox Body Build

Want more power than your Fox body's 5.0l block can handle? Need to keep your build on a budget? Why not use the tried and true 351 Windsor? This truck motor has been a staple of the Mustang scene for years, making installation easy and inexpensive with the right parts.

Why Use a 351W?

The 351 Windsor and the 5.0 use the same basic block design, so dropping the bigger motor into a Fox body is fairly straightforward. However, the difference is greater than just displacement: the 351 has a much stronger block and can be stroked well beyond the limits of the 5.0, greatly expanding performance potential. Windsor motors were used in trucks until 2001, making used motors readily available.

Of course, since these motors are built for trucks, the intake and exhaust are heavily restricted to maintain velocity at low RPM. If you drop a stock motor in a Mustang, you'll find that you have massive amounts of low end grunt and very little else. Fortunately, 351W's built from 1977 onward used the same head castings as the 5.0, letting them use the same performance heads. You could take a shortcut and use a crate motor like one of Ford Racing's Boss 351-based motors.

What do I Need to Make the Swap?

This engine swap is popular, so there are plenty of off-the-shelf parts available to get this motor to fit your Fox body.

Oil pan, pump, shaft and pickup:

The 351W has a front sump oil pan, while the 5.0 is rear sump. We have kits available with all the parts to make your 351 rear sump so it clears the K-member.

Flywheel and harmonic balancer: 

The 351W needs a 28oz imbalance, while the 5.0 uses a 50 oz imbalance. The flywheel needs both the correct imbalance and the correct bolt pattern for the 351. Bell housings are identical for these motors, so it will bolt right up to your current transmission.

Headers: 

These need to be designed for the swap due to limited space in the engine compartment with the bigger engine.

Intake manifold:

 A wider lower intake manifold is needed due to the 351's higher deck height.

Hood and/or motor mount spacers: 

The increased deck height will result in a total increase in height once the intake is in place, which can interfere with the stock hood. Motor mount spacers may be able to drop the engine low enough to clear the hood, but if you're running a tall intake with a carburetor, you may need a taller hood or a hood scoop.

Accessory brackets:

Setups vary, so there's no clear checklists of parts needed to get the accessories to fit. Sometimes, just some new brackets are needed, while on some motors a crank spacer is needed to get the belt to line up with all of the pulleys.

Where Can I Get These Parts? Anderson Ford Motorsport carries everything you need to get the most out of your Mustang, including all the parts you'll need for a 351W swap. Want to turn that truck motor into a monster? We have parts for that, too, including our own line of camshafts.