Ford Four-Valve Head Information Guide - Six Times Four
Which Of The Six Available Four-Valve Head Designs Is The Best Match For Your Combo?
While most Four-Valve modular owners are familiar with both B and C DOHC heads, few have even heard of the requisite A head that preceded them both. The first DOHC heads designed by Ford featured a dual-intake-runner/single-injector setup similar to the second-generation B heads. But since the As never made it to production, we're left with nothing but speculation concerning their performance capabilities. In this case, B is for "Better."
When broken down into its most basic elements, the explanation of why four valves are better than two seems extremely simple. As an engine is essentially a large air pump, it follows that the greater valve area (or potential flow area) inherent in an optimized Four-Valve head design will ultimately allow for more airflow (at all lift levels) than a similarly designed and optimized Two-Valve casting. Though basic dual-overhead-camshaft, four-valve-per-cylinder-head architecture has been around for more than 75 years, domestic manufacturers were slow to adopt the less conventional valvetrain design in anything but small-displacement, four-cylinder econoboxes until the early '90s.
Chevrolet's (Lotus-designed and Mercury Marine-built) 5.7L four-cam LT5 ZR-1 motor gets credit for being the first domestic production application of Four-Valve technology on an eight-cylinder engine (1990). But, it was Ford's modular Four-Valve designs that truly paved the way for those carrying the domestic overhead-cam performance banner in the mid and later parts of the decade. During the last 11 years, Ford has designed and produced no less than six different production modular (4.6 or 5.4 compatible) Four-Valve heads, and five of those have come in the last 5 years.
As anyone attempting a Four-Valve swap into a late-model GT, or those with '96-'01 snakes wanting to upgrade to newer Four-Valve heads will contest, modular DOHC head selection can be a scary thing. After all, as previously stated, there are six different production head castings from which to choose (five if you don't want to count the thousand or so '00 Cobra R heads cast), spanning from a production run that dates back to the '93 Lincoln Mark VIII. Just about any well-versed modular fan can tell you that there are zero aftermarket head offerings-other than those of Ford's own in-house speed shop, Ford Racing Performance Parts-available for modular connoisseurs today. Dual-overhead-cam modular owners shouldn't fret, as the silver lining to this otherwise dark cloud is the fact that aftermarket heads are not required. Ford's original-equipment Four-Valve heads have been used successfully on everything from its silky-smooth, luxury SUV line to 114-octane-swilling, six-second drag racers.
In order to assemble the most comprehensive and accurate Ford Four-Valve head information available, we enlisted the help of several premier modular engine builders. Racer/builder Al Papitto of Vero Beach, Florida, is the owner of Boss330racing.com and an '00 Cobra R-based, naturally aspirated, 5.4 '97 Cobra that is perilously close to the nine-second zone at a portly 3,400 pounds! Al cut his teeth in the ranks of Pro Stock motorcycle and Alcohol Funny Car racing, and has only recently begun to share his extensive overhead-cam engine-building experience with the Mustang community.
Likewise, James Hensler, owner of Hensler Racing in Reynoldsburg, Ohio, has been nothing short of a pioneer in the field of nitrous-assisted Ford Four-Valve racing. James is the pilot of a Nitrous Express-fortified, big-bore-modular- powered NMRA Renegade car. Look for him to eclipse last season's previous best of 9.30 at 150 by a large margin this year, with his Fox Lake-ported B heads/HCI intake top end finding a new home atop a 305ci big-bore short-block.