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The Two-Valve Twist: Installing Trick Flow Twisted Wedge® 185 Cylinder Heads

Owners of Ford 4.6L and 5.4L Two-Valve modular V8s, your wait for a true performance cylinder head is over. Actually, it's been over since 2009—that's when Trick Flow Specialties introduced the Twisted Wedge 185 aluminum cylinder heads. They are the first (and so far, the only) true aftermarket performance heads for the Two-Valvers.

Why did it take this long to make a cylinder head for an engine that's been around almost 20 years? We think the timing is just about right. For example, there are gazillions of Two-Valve engines available for cheap in the nation's boneyards. The short blocks can handle up to HOW MUCH HORSEPOWER? with no modifications. Camshafts, induction systems, headers, superchargers, and other hop-up parts are on the shelves. Add in the airflow provided by the Trick Flow heads and you have the perfect storm of serious Two-Valve horsepower.

The Return of the Twisted Wedge

The Twisted Wedge name was first used for Trick Flow's groundbreaking 5.0L aluminum heads, introduced in 1995. (Those heads are still available in myriad versions for street and drag racing). It describes Trick Flow's patented combustion chamber design, which rotates, or twists, the intake and exhaust valve angles and moves the spark plug closer to the center of the cylinder bore. These changes unshroud the valves to increase airflow volume, and help promote more complete combustion.

Trick Flow took a similar approach with the Twisted Wedge 185 heads. Ford's design put the valves single-file on the exhaust side of the head, which greatly restricts airflow. This design also limits camshaft size due to valve-to-piston clearance with the factory dished pistons. Trick Flow engineers moved the intake valves to the opposite (intake) side of the head. This put them directly in line with the intake ports and created the "twisted" combustion chamber design so conducive to airflow. The design also accommodates wide cams up to 245 degrees duration @ .050 and .600 inches of lift with wide lobe separation angles (LSA), and mid- 230 degree duration cams with narrower LSAs. That is a significant improvement over the stock 4.6L heads.

The Twisted Wedge 185 heads retain the port shapes and locations of the factory Power Improvement (PI) heads, so PI-compatible intakes and headers can be used. However, Trick Flow opened up the intake runners to 185cc and recontoured them to smooth out the airflow path. The intake and the 93cc exhaust runners are as-cast, but are based on CNC-ported profiles. These "Fast-As-Cast" runners provide high flow rates without the expense of actual CNC-porting. The process is a Trick Flow exclusive.

The Twisted Wedge 185 heads have another "why didn't we think of that" feature: removable cam bearing journals. Factory 4.6L heads have cast-in journals with a removable cap (Windsor) or a removable cap "girdle" (Romeo). The cams ride directly on the journals. If the valvetrain lets go and the journals are damaged, the heads turn into aluminum doorstops. Trick Flow developed a forged powdered metal, four-bolt cam journal precisely located on the head and completely removable. If the caps are ever damaged, you can ring up Trick Flow for a set of replacements and put your Twisted Wedge heads back into service.

The Twisted Wedge 185 heads are available with your choice of 38cc or 44cc CNC-profiled combustion chambers with 1.840/1.450 inch stainless valves. The 38cc chambers yield about 10:1 compression on a PI short block; the 44cc chambers deliver the same compression ratio for non-PI (1996-98) short blocks.

The heads come fully assembled with stainless valves, 1.100 inch beehive valve springs, chromemoly retainers, and forged steel locks. The standard Twisted Wedge 185 heads come with springs rated at 90 lbs. seatd/205 lbs. open pressure. The springs can handle up to .600 inches of valve lift. Trick Flow also offers the Twisted Wedge Track Heat 185 with stiffer springs (125 lbs. seat/275 lbs. open pressure) for engines with higher compression or a power adder like nitrous and superchargers.

To demonstrate the horsepower awesomeness designed into the Twisted Wedge 185 heads, Trick Flow bolted a pair on a 50,000 mile Two-Valver from a 2002 Mustang GT. To take advantage of the extra airflow, Trick Flow also added one of its Track Max Stage One cam sets, a Track Heat intake manifold, 30 lb.-hr. TFX fuel injectors, an SFI-approved harmonic damper, and a timing chain kit with adjustable crank gears. The net worth of all this stuff is around 408 horsepower—over 100 horsepower more than a stock 4.6L Two-Valve delivers.

That's a big checkmark in the win column.

Parts List

TFS-TFS-51900001-M38   Trick Flow Twisted Wedge 185 cylinder heads, 38cc chambers, pair

TFS-51802001   Trick Flow Track Max hydraulic roller cam set, .550" lift

TFS-51800002   Trick Flow Track Heat intake manifold, 75mm upper, silver powdercoat

TFS-24075         Trick Flow TFX 75mm throttle body, each

TFS-89030         Trick Flow TFX 30 lb.-hr. fuel injectors, set of 8

TFS-51800520   Trick Flow timing chain set with adjustable crank gear

TFS-19009         Trick Flow harmonic damper, SFI 18.1-approved, each

TFS-51800801   Trick Flow cast aluminum valve covers, 11-bolt/Romeo, silver powdercoat, pair

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