Jesse Allen of AMP Performance puts the finishing touches on Jose Casas' newly top-halfed
Making Mustangs stronger by way of performing a cylinder heads, camshaft(s), and intake manifold swap has a long history with our Mustang hobby. Yes, the infamous HCI," exchange is a tried-and-true performance upgrade for bone-stock Ponies of any vintage, and over the years, we've presented many derivatives of the top-half trio for 5.0-liter engines using aftermarket pieces that we feel offer enthusiasts the best bang for their hard-earned bucks every time the throttle hits the floor.
It has only been a short time that we've been able to explore the effects of a full "top-half" exchange on Ford's 4.6-liter modular engine. Prior to 2006, complete upper-end upgrades for modular Mustang engines had been somewhat limited. Despite camshaft development and a wide variety of CNC-ported heads being offered for Two-Valve and Four-Valve bullets, affordable, non-custom intake manifolds for either were virtually nonexistent.
The Three-Valve engines of '05-'10 Mustang GTs unfortunately suffered from the same limitations with regard to development of affordable, aftermarket intake manifolds. It took nearly two years for sheetmetal pieces to hit the S197 scene, and an additional 365 days before a bolt-on, cast intake left the foundry. One of the reasons for the long delay is the fact that the factory-installed, composite intake is a solid piece in its own right-performing well on stock engines, and also holding its own on engines that are upgraded naturally aspirated mods and power adders.
Despite the manifold's great efficiency, however, engineers at Ford were forced to consider making improvements after studying the stock intake's effect on the engines in Ford Racing's FR500C Continental Challenge Mustangs. Basically, the stock piece's small runners choked the high-winding trey-valve, just as it hit the sweet spot in its power band (approximately 6,000-6,500 rpm). The result of all the intensive research and development is Ford Racing Performance Parts' new Three-Valve intake (PN M-9424-463V; $599.95), which was finally dispersed to the masses in 2010-nearly four years into S197's production before releasing its new manifold.
The arrival of FRPP's long-awaited Three-Valve intake piques our strong interest in seeing how it performs in a naturally aspirated environment, as one of the major players in a good, old H/C/I swap. That's right-no nitrous, blowers, or turbochargers are being used in this experiment. However, based on the intake's high-flow runner design, Three-Valve cylinder heads, and the general dynamics of modular engines, we suspect the new piece probably is exceptional when used with power adders. That's long been the case with its aftermarket Two- and Four-Valve counterparts, which have more than made their mark on boosted '99-'04 GTs, Mach 1s, and Cobras.
While we've experimented with two-thirds of the Three-Valve HCI swap in the past (bolted on various ported heads and higher-lift cams), we're excited about finally being able to take this type of performance testing all the way. The Mustang specialists at AMP Performance of Phoenix, Arizona, offer two upgrade packages for naturally aspirated S197s that we're checking out in this tech effort. Both performance systems are founded on the new intake manifold. They're amenable to enthusiasts on simple budgets (FRPP's manifold, CAI, and 62mm throttle body; $1,453 plus labor), as well as those who can afford to spend a bit more for serious "all-raw" power (everything in System 1, plus Fox Lake Power Products' ported Three-Valve cylinder heads and Comp camshafts; $4,443).
Your tech editor joined AMP's shop boss, Chris Ciolek, and technician Jesse Allen for a marathon parts-on/parts-off evaluation of both packages. The end results of all our efforts were outstanding, as you'll see when you read through this report in its entirety. Be sure to fully process the all-important dyno data.