Ford Mustang GT - Affordable Two-Valve 4.6 Engine Intake Manifold - Typhoon Warning

The wait for a performance-bred, mass-market intake manifold for Two-Valve modular engines has been a long one, indeed. While the aftermarket has addressed many areas of mod-motor performance over the years, the intake manifold has been somewhat of an Achilles heel.

Cost is one of the major reasons mass production of an aluminum intake manifold for 4.6 engines has been so slow. Yes, a few companies have designed and produced high-performance manifolds for the Ford modular engine. But these intakes are geared more toward aggressive modular engine combinations. Also, the great amount of time it takes to produce these intakes has forced manufacturers to set retail prices beyond what those raised on $500 5.0 manifolds are used to paying (more than $1,000), when the return on investment is far below the 30 or so horsepower one would expect from such a pricey part.

Professional Products, a Hawthorne, California-based company known for its Power+Plus Typhoon series of intake manifolds (for carbureted and EFI, pushrod small-block Fords), has joined the mod-motor manifold mix with its latest Typhoon. It's an aluminum, three-piece deal for '99-'04, Two-Valve, 4.6 engines (the intake can also be used on '96-'98 engines if '99-up heads are used).

The new manifold, developed in conjunction with horsepower guru Rick Anderson of Anderson Ford Motorsport, features shorter runners than those of OEM intakes and a radical, tri-level plenum chamber. The lower plenum basically is the section where all the horsepower magic happens, according to Rick, who logged hundreds of hours on the flow bench with a prototype of the new Typhoon, focusing on port shaping, runner size, and perfecting those critical areas of the manifold.

Rick also conducted exhaustive tests on the chassis dyno (200 pulls) with the manifold bolted to the 4.6 engine in Josh Kilday's '01 Roush GT. Josh's ride already had a host of bolt-on upgrades, which included a D.S.S. short-block, Fox Lake Stage II heads, Anderson's N-42 camshafts, Professional Products' 75mm throttle body and upper plenum, a Bassani exhaust, and 4.10 gears. The modified mod produced more than 310 hp and 315 lb-ft of torque with a stock intake, throttle body, and plenum when they were installed on the motor for baseline numbers.

"We had the prototype intake on and off the motor a total of 11 times while developing the Typhoon," Rick said. "We ultimately saw gains of nearly 26 hp (over the stock manifold and throttle body/plenum) at the rear wheels, and learned that the Typhoon really comes on strong between 5,000 and 6,500 rpm. What's great is that there is no significant drop or loss of power whatsoever at lower rpm, so a Mustang's street manners are going to be about the same as a stocker's with this manifold, especially in the 4,000-rpm range."

While a preproduction Power+Plus Typhoon is shown in the accompanying photos, the actual finished intakes will be available in two versions: polished (PN 54060; $700) and satin (PN 54061; $550). The manifolds are a direct, bolt-on upgrade and will accept all the same factory accessories (sensors, fuel rails, alternator, and so on) that are found attached to stock manifolds. The three-piece construction makes the Typhoon a veritable porter's dream. The lower plenum, where air is literally sucked off the walls thanks to smooth radiuses and perfect corners, can be accessed by simply disassembling the manifold and getting busy with the porting tools, then putting it all back together when the work is done.

Here's a look at the preproduction manifold being taken to task by the crew at Anderson Ford Motorsport. The market has been waiting a long time for a 4.6 intake like this one, with more than 25 bolt-on horses and plenty of room for more with a little modifying. And getting one won't set you back a G-note, so we're glad to see this Typhoon on the radar.

Intake on . . . intake off. Rick estimates that Josh's engine experienced no fewer than 11 instances where it looked like this, with the manifold off, during the development and testing of the Typhoon.

Here's a side-by-side comparison of the stock intake manifold (right) and the new Power+Plus Typhoon intake by Professional Products (left). The two look almost the same on the surface, but thanks to Rick Anderson's handiwork, the Typhoon blows away the stocker when it comes to making power.

The underside is the Typhoon's serious side, and it unfortunately goes unseen (left) when it's sitting on an engine. The manifold's unique, three-section design consists of short runners and a lower plenum that's ready and waiting for porting.

The Typhoon is a direct bolt-on for 4.6 mod-motors with '99-'04 cylinder heads and has bungs and provisions for all the OEM sensors, injectors, fasteners, and such. It's definitely a drama-free manifold that doesn't require additional hardware or modification to install.

Rick always uses his Power Pipes to eliminate inlet restrictions for this type of evaluation. Here, TJ "Doogie Howser" Clark connects the tube to the Professional Products 75mm throttle body and plenum.

Josh Kilday's 'Stang stood up to 200 pulls on Anderson's chassis dyno, and ultimately showed us that the Typhoon gets it done for the Two-Valve engine.

Horse Sense: Looks are deceiving. At first glance, the new manifold looks as if it's just an aluminum copy of the plastic stocker we've all grown to hate. You definitely can't judge an intake by its cover. This thing's a whole lot better!

While it isn't a torque monster (an average torque value of 319 lb-ft remained consistent throughout the test phase-a gain of only 2 lb-ft over the stock manifold), Professional Products and Anderson Ford Motorsport have come up with something that socks it to the 4.6-liter when it comes to making raw horsepower without breaking the bank.

Josh's Roush pumped out 310.60 hp and 316.98 lb-ft of torque in an initial dyno test with a stock intake, throttle body, and upper plenum. These figures were used as a baseline, and better numbers came about quickly. When Rick added Professional Products' upper plenum and 75mm throttle body to a stock intake manifold, horsepower increased to 317.06 and the plenum/throttle body combo proved to be the source of the aforementioned 2-lb-ft torque gain, as that number rose to 319.10. The final iteration of Anderson's testing was done with the Typhoon and Professional Products upper plenum/throttle-body package. In this trim, the Two-Valve engine spun off 326.08 hp and held steady on the torque side, at 318.95. When compared against a stock, plastic intake, the Typhoon boosted horsepower by a ton.