K.J. Jones
June 1, 2007
Photos By: Courtesy Of Sutton High Performance
Sutton High Performance Technician Bryan Stepinski puts torque to Ford Racing Performance Parts' new CNC-ported, Three-Valve cylinder heads. Randy Mohrbach's moderately modified '06 Mustang GT is our test mule for this project.

Horse Sense: The heads/cam/intake threesome has been an upgrade staple for 5.0 Fords for what seems like an eternity. Recently introduced and affordable, aftermarket aluminum intakes now make the same type of package possible for the Two-Valve 4.6s. With the rapid rate of development for S197 mods, it probably won't be too long before FAST's Three-Valve manifolds are ready. Our focus right now is heads and cams, but you can bet we'll bring you all the dope on a complete, top-end, Three-Valve heads/cams/intake ensemble once all the pieces are in place.

At this point, it's almost impossible to disagree with the idea that we're living in the "modular age," regarding engine technology for today's Mustangs. The period dates back to 1996 when the Two-Valve 4.6 made its way between a Mustang's fenders for the first time. Many pushrod-loving 'Stangbangers cried foul initially, but now it seems even the most die-hard disciple of the 5.0 either owns, or is somehow involved with, a modular 'Stang.

The 4.6 trey-valve in Randy's 'Stang had already been treated to a good assortment of bolt-ons, including JLT's S197 True Cold-Air system (red tube in photo). The system shined in the horsepower and torque departments in a head-to-head comparison test we featured in our Jan. '06 issue ("Cold Score," p. 84).

One thing we find ironic when 4.6/5.0 comparisons are made is-while aftermarket cylinder-head development took off and hasn't stopped advancing for all types of small-blocks and pushrod V-8s that power Fox Mustangs-there really hasn't been any progress made toward production of new high-performance single-, and dual-overhead-cam cylinder heads that sit atop 4.6 engines.

CNC-ported heads (from stock PI castings) and quick-rev camshafts are among the true hot performers for the modular crowd. We've done several studies that detail how they increase an engine's air and fuel flow, as well as horsepower and torque gains that usually result from bolting these components on '99-'04 4.6 GTs and '03-'04 Cobras.

Due to the ever-growing popularity of the S197 Mustang and our need to know about anything new that might improve the car's performance, we turn our focus to Ford Racing Performance Parts' latest offering: CNC-ported Three-Valve heads (PN M-6049-463P; $1,399/each) and Comp Cams' new Xtreme Energy camshafts for Three-Valve modular heads (PN 1273000; $599).

Unlike removing or replacing heads on a 5.0-powered Fox, which can be done with the engine still in place, head swaps on an S197 'Stang require complete removal of the 4.6. Bryan uses the "raise the car/lower the drivetrain" method for attaining access to the heads. He has them off in no time.

Randy Mohrbach, Service Manager of Sutton High Performance in Matteson, Illinois, owns this '06 Mustang GT. His car has been treated to many of the latest upgrades for S197s, such as underdrive pulleys, a JLT cold-air system, FRPP intake-runner deletes, a Pypes after-axle exhaust, and 4.30 gears. Trying FRPP's ported heads and Comp's new camshafts seems like a logical next step.

Sutton's technician duo of Andy July and Bryan Stepinski took care of the parts-swapping for this project. Dyno Specialist Jerry VanDerLinde handled PCM calibration using SCT's Advantage III tuning software and an Xcalibrator 2 hand-held flash tuner.

The test 'Stang's performance was evaluated in three phases (baseline, CNC heads with stock cams, and CNC heads with Comp cams) on Sutton's Dynojet chassis dyno. To speed up the test process, Comp Cams' Beehive valve springs (PN 26113) were installed on the ported heads and used with the stock camshafts. Read on for photos and the all-important dyno information that details how things went.