S197 Mustang Heads And Cams - CNC For Three

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.

Click here for the S197 Mustang heads and cams dyno chart

Here's a close look at the valve configuration on one of Randy's stock cylinder heads. Thanks to the extra intake valves and the greater volume of air that moves in and out of the cylinders, these heads can produce more horsepower without porting than their Two-Valve counterparts. We've tested Three-Valve engines with power adders and made much more than 400 rwhp, which says a lot about the stockers' potential.	Ford Racing's CNC program improves the D-shaped exhaust ports by adding approximately 30 percent more flow. Exhaust gasses travel along the roof area of these ports, but at a high velocity. While a naturally aspirated 4.6 might show about a 5 percent gain in rear-wheel power, the same engine with a blower, turbo, or nitrous shot will certainly produce more impressive power numbers with exhaust flow like this.	Three-Valve heads feature short, rectangular intake ports that practically drop straight down into the combustion chamber. This CNC portwork on the intake side increases flow by about 20 percent, meaning a lot more air and fuel is going to be combusted when Randy's modular is at full scream on the dyno.
What you see is what you get. FRPP's CNC-ported heads (PN M-6049-463P; $1,399/each) are sold assembled with production springs, valves, retainers, locks, and seals. The heads don't include camshafts, followers, or hydraulic lash adjusters, but that's where acquiring Comp's Xtreme Energy setup becomes a wise choice.	Comp Cams' Xtreme Energy 261H-15.5 camshaft set (PN 127300; $599) includes cams designed to work with the Three-Valve engine's variable cam-timing system. VCT basically retards the engine's timing at peak power. Because of the cams' advance at low rpm and the ability to keep closing points of the intake valves fairly similar, throttle response is improved and both low- and high-rpm performance is optimized. The camshafts each have a profile of 0.490-inch (intake) and 0.480-inch (exhaust) lift, and 0.222-inch (intake) and 0.235-inch (exhaust) duration at 0.500.