Replacement Air Filter for '86-'93 Mustangs

Step By Step

View Photo Gallery

Moroso’s high-flow air-induction system (PN 65847) can be installed on any ’89 to ’93 5.0 Mustang. It includes stainless clamps, a steel mounting plate that uses the original bolt holes, a plastic tube that connects to the factory 60mm Ford mass air meter, and a K&N air filter.

Remove the factory airbox by unbolting it from the inner fender and disconnecting it from the mass-air meter rubber boot. Also remove the silencer and the rubber isolators that hold the box to the inner fender.

Insert the inlet tube through the matching slots in the fenderwell plate and rotate it 90 degrees.

Install the tube and plate in the inner fender and bolt the setup to the fender with the supplied bolts and washers. Attach the other end of the tube to the mass air meter rubber boot.

The filter fits up inside the fender from outside the car and installs onto the part of the plastic tube that protrudes into the inner fender. It secures to the tube with a supplied hose clamp, though an extra fabricated support bracket might be beneficial.

The finished installation looks clean and totally hides the air filter. We had the system installed in about half an hour.

The stock air-filter box in ’86 to ’93 Mustang 5.0s is not exactly the prettiest thing in the world. Besides that, the panel air filter contained inside has to get its air from a small, oval-shaped hole on one side of the box.

This replacement induction system from Moroso eliminates the air-filter box and relocates a new K&N filter inside the front fender—away from the hot air in the engine compartment. Moroso claims this system flows more air than the stock airbox and that the system adds about 11 hp to an otherwise stock ’89 to ’93 5.0 Mustang.

The Moroso kit is designed to work with a stock mass air meter, but we bolted the system on a more radical car that uses a Ford Motorsport 80mm mass air meter as found on ’96 to ’98 Mustang Cobras and Lincoln Mark VIIIs. Along with the bigger meter comes an aftermarket piggyback chip that alters the air/fuel and timing parameters of the stock EEC IV programming. This combo controls a 5.0-based, 347 stroker small-block. When we installed the Moroso duct on the car, idle quality was affected during cold starts, but it ran great while cruising. We suspect some additional chip tuning with the Moroso setup in place would fix the idle problems we encountered, and the system is certainly a slick upgrade for less-modified Mustangs—especially when you consider how easy it is to install.