We can well remember the introduction of the new 4.6 modular motors in the Mustangs in 1996. Being die-hard 5-liter Ford fans, we were concerned about Ford's decision to abandon the little small-block that had served it so well since its inception back in 1962.
Ford offered the new 4.6 versions with two distinct powerplants. Though both shared the same displacement, the wilder SVT Cobra version had an aluminum block and was topped with free-flowing aluminum cylinder heads that featured double overhead cams and four valves per cylinder. The powerful and more expensive SVT Cobra was obviously the most desirable, but the vast majority of V-8 Mustang buyers opted for the GT.
These folks got a milder SOHC engine that featured just two valves per cylinder. The overhead cam configuration promised plenty of rpm potential, but unfortunately the mild Two-Valve modular never fulfilled that promise. In fact, the original Two-Valve 4.6 was less a revver than the pushrod 5.0 H.O. The maximum torque production came near 3,500 rpm-something that helped provide the motor with the illusion of performance, but things quickly went flat as the tach needle swept passed 4,400. Rated at 215 hp, the buying public reacted accordingly, and Mustang sales went in the toilet.
With the lowest power rating of all the available 4.6 Mustangs, the '96 (and '97) GT is unquestionably the redheaded stepchild of the modular engine family. Always seeing the glass half full here at MM&FF, we decided on a new project. While the '96 GT is certainly low man on the performance totem pole, there is a plus side to the lack of desirability-cost. Unlike the later PI motors or even the '97-'98 versions, a '96 Mustang GT can be had for a song. Our '96 five-speed GT was purchased for the paltry sum of $4,000 (from the original owner, no less). While the 260hp PI-motored Mustangs may offer better performance in stock trim, just how long do you think you will leave the new project stock?
The idea is to demonstrate that there is power to be had from the early non-PI motors (and Mustangs in general), even without resorting to the usual '99-up head and intake upgrade. We hope to take the non-PI motor (sans anything resembling PI components) to 300 rwhp in normally aspirated (pump-gas streetable) trim. After that, we may turn to PI upgrades but will certainly go for forced induction (we already got waxed by an LS1 Firebird). With power taken care of, look for a full suspension upgrade, big brakes, and maybe even a body kit. Given the lack of desirability of our Laser Red Mustang, we decided the ideal name for her was Project Redheaded Step Child (RSC).
RSC was purchased in stock trim. The '96 Mustang GT sported a five-speed tranny and nearly 200,000 miles. The original owner commuted nearly 140 miles per day to and from work. A discussion during purchasing revealed that the tremendous mileage logged on the freeway allowed him to use the original brake pads for 94,000 miles. He said he needed to stop only five times from his house to the freeway; the rest of the time was spent with the cruise control set at 70 mph.
The first step toward our normally aspirated performance goal of 300 rwhp was to install a few minor modifications. These basics are popular due to their price and ease of installation, but as we found out, the stock motor was not really airflow restricted-a fact we hope to change once we improve the power output with wilder cam timing, ported (non-PI) heads, and long-tube headers.
The list of performance upgrades for this go-round included a mass air meter and filter from C&L. C&L also supplied a cast-aluminum intake tube (from the MAF to the throttle body) to replace the corrugated rubber production hose. C&L was nice enough to include one of its upper intake (elbows) while Accufab supplied the matching 75mm throttle body. We know from testing that the throttle body and elbow are usually worth power on the later PI motors (especially modified ones), but would the stock non-PI motor take advantage of the extra airflow?
Before tearing into the motor...
Before tearing into the motor with reckless abandon, we thought it would be a good idea to start with a few basic bolt-ons. Our eventual goal for Project Redheaded Step Child is 300 rwhp from a non-PI engine, and these minor mods are the first step toward reaching that goal.
C&L supplied this mass air...
C&L supplied this mass air meter and filter assembly for our '96 GT. Not shown is the filter shroud designed to shelter the filter from engine heat, forcing it to draw ambient air from the fenderwell.
C&L also supplied this cast-aluminum...
C&L also supplied this cast-aluminum air-intake tube designed for installation between the MAF and throttle body.
The final performance product...
The final performance product supplied by C&L was this upper intake, or inlet elbow. The C&L inlet elbow easily outflowed the stock unit, but the real question was whether our stock 4.6 could take advantage of all that extra airflow.
C&L recommended a 75mm Accufab...
C&L recommended a 75mm Accufab throttle body to feed the inlet elbow. We had excellent results with this combination in previous testing on wilder combinations.
The gains offered by the BBK...
The gains offered by the BBK underdrive pulleys increased with engine speed. Like the throttle body and intake, the pulleys offered 6-7 hp past 5,000 rpm.