KJ Jones Senior Technical Editor
December 21, 2009
Photos By: KJ Jones

Horse Sense:
Since we're covering a boatload of territory with this report, some of the general "how-to" information that is associated was purposely been omitted. This was done to ensure that we'll have page space for more focus on the long-awaited heads and camshafts, as well as all of the dyno-test results (especially with the Twisted Wedge heads installed and a custom tune loaded into our test mule's PCM) from our extensive project.

There's no arguing that we're forever indebted to 5.0-powered Fox Mustangs. Ponies of 1979-to-1993 vintage are the foundations of our hobby, and to this day, they're still highly regarded as being the best Mustangs to modify. However, despite our high regard for Foxes, New Edge Mustang GTs of '99 to '04 are fast becoming the proverbial "Ponies to own," among the younger members of the 'Stang Nation.

Thanks in part to the huge success of Ford's S197 ('05-'09) platform and also the brand-new '10 Mustangs, the 4.6-liter New Edge GTs are gaining popularity nowadays because they're being sold for minimal dollars by enthusiasts who are stepping up to the newer models. Because of this new abundance of mostly virgin 'Stangs and an aftermarket that has noticed the resurgence of '99-'04s, just that quickly we're sitting on another Mustang style that may become as revered as its predecessor.

We've watched the development of and evaluated many performance products for the 4.6-liter, Two-Valve modular engines that power New Edge GTs. These pieces range from entry-level CAI systems to full-tilt power adders. Most of them have been deemed capable to helping make considerable improvement to a stock Two-Valve engine's horsepower and torque output.

In addition to testing those bolt-on upgrades, one of the projects that we've wanted to do for a long time is hop-up a New Edge 'Stang's stock Two-Valve bullet with a performance-minded "top half," consisting of improved cylinder heads, bigger camshafts, and an intake manifold. The only problem we had in doing this was the lack of non-stock pieces-mainly cylinder heads-for the 4.6 Two-Valve. While cams and even new, aluminum intake manifolds for '99-'04 GTs had come to fruition, ported versions of Ford's Performance Improved cylinder heads had been the mainstay for upgrading the top-half of a modular engine.

Not to knock ported PIs, as we have them on our own '02 GT project car (the one with the ProCharger F-1A on it) and they do the job just fine. What we wanted to see were completely new cylinder head castings for the Two-Valve mod motors, similar to high-performance heads for pushrod engines that are designed to meet almost any type of street or racing need.

Engineers at Trick Flow are serious about making big steam with small-block Ford engines (pushrod or modular), and over the years the company's Twisted Wedge cylinder-head series has become a thing of legend in the 5.0 Mustang community. Introduced in 1996, TFS's aluminum Twisted Wedge castings brought a dramatic change in the conventional design of small-block Ford cylinder heads.

These heads feature reshaped/twisted combustion chambers that allow more efficient airflow to bigger valves (which are installed at slight angles for improved clearance between the valves and pistons) and the combustion chambers. When complemented with an appropriate intake manifold/camshaft combination on otherwise stock engines, the heads proved to be serious contributors to 5.0s making bigger steam.

Today the Mustang hobby is firmly planted in the modular age now, and as mentioned earlier, with Two-Valve performance really starting to shine, Trick Flow again stepped to the front and created a new version of the Twisted Wedge cylinder head, specifically designed for 4.6- and 5.4-liter Two-Valves.

Trick Flow's all-new castings (PN TFS-51910001-CNC/38cc, TFS-51910002-CNC/44cc) are every bit as impressive as their older siblings were when they came onto the Mustang scene back in the day. The modular Twisted Wedge heads are made from T61 Aluminum, and feature increased port volume over Ford's PI castings, as well as unique 1.84-inch intake and 1.45-inch exhaust valves.

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