July 19, 2006

Memphis, Tennessee, has long been the cradle of the aftermarket performance industry, second only to Los Angeles. So, it should come as no surprise a legendary name like Racing Head Service (RHS) would have come of that Memphis racing spirit some 39 years ago.

RHS was the brainchild of our good friend, the late Ivars Smiltnieks, who founded the company with Bob Woodward and John McWhirter, and later, Scooter Brothers, to serve fellow racers. When the company began in 1967, it was a manufacturer of racing cylinder heads at a time when few others were in the business of making them. What's more, it began in Smiltnieks' garage in suburban Memphis. Through the years, RHS became a respected builder of everything from racing engines to turnkey race cars.

We like the crisp, clean, CNC machine work, which eliminates the potential for exhaust leaks. These exhaust ports are set up for two types of header flanges, which makes these heads versatile for different applications.

As RHS grew, it became a name successful NHRA and roundy-round racers came to for solutions-and power. It pioneered the crate engine in the '80s, delivering turnkey engine packages to satisfied customers. Ultimately, Smiltnieks became the sole owner of RHS when Woodward and McWhirter retired. Scooter Brothers moved on to Comp Cams.

Always innovative, RHS produced untold thousands of high-performance crate engines, cylinder heads, and other components for enthusiasts around the world. Smiltnieks passed away from a stroke many years ago, but the spirit he instilled in RHS never died. The same folks who bring us Comp Cams, FAST, TCI, ZEX Nitrous, Powerhouse Products, Pro Racing, and AETC Engine Technology have brought back RHS, along with an exciting crop of new Ford cylinder heads.

You might be tempted to ask what happened to RHS and why it's back today. A change of ownership and short-term change in priorities at the Comp Performance Group put RHS on the back burner beginning in the late '90s. RHS never ceased operations; it just went dormant. The Comp Performance Group in Memphis has been waiting for the right time to bring RHS back. It wasn't going to do it with a cookie-cutter selection of lame cylinder-head castings just to compete in the cylinder-head business. The Comp Performance Group has never done anything that way.

Think of the Comp Cams name and reputation for performance and you'll agree-RHS wasn't going to be anything less than exceptional. It would get back into the cylinder head business with well-thought-out products, and we're here to tell you all about it.

Today's RHS is an international undertaking between the Comp Performance Group in Memphis and Mike Morais of Southern Performance Ltd. (SPL) down under in New Zealand. This is the beauty of a global economy and an ever-shrinking planet. It brings great talent together from around the world, eager to create exceptional products. Morais has extensive casting and machining experience, which brings us an extraordinary lineup of cylinder heads for small-block Fords.

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Power by Design
Factory Ford small-block heads have always been limited by small intake and exhaust ports, which limit flow, exhaust scavenging, and power. RHS decided to aggressively go after these shortcomings with its own fresh approach to the small-block Ford head. This approach came from down under at SPL in New Zealand.

The Pro Action cylinder head yields flow numbers that promise significant improvements in performance depending on how you build your engine. Figure in greater exhaust port volume, which helps scavenging. When scavenging improves, flow through the head improves dramatically. Intake runner volumes are 180, 200, and 215 cc, respectively, which give you three intake volumes from which to choose. The size you select depends on how you intend to use the engine. The 180 and 200ci intake runner sizes are more appropriate for street and strip use. A larger 215cc runner makes more sense for a stroker engine or for all-out racing because velocity comes on strong at high revs where racing engines live. Smaller runner volumes provide velocity (and torque) at lower rpm ranges, which make them more appropriate for the street and occasional racing.

Impressive flow numbers come from not just from runner volume, but how these runners manage airflow. Pro Action runner design eliminates turbulence, which makes the most of airflow. Improved airflow also comes from the way RHS radiuses the valve faces and seats.

RHS cylinder heads are unlike anything else you've seen because the Comp Performance Group started with a clean sheet of paper-and Clean Cast Technology. The unique RHS vertically integrated manufacturing process allows engineers to follow and control every detail of cylinder-head production. They follow the process from CNC-design to assembly, ensuring the best quality from a high-performance cylinder head. What's more, RHS does it all in one facility. Heads are designed, cast, machined, and assembled in the same location. This is an industry exclusive.

RHS management and engineers wanted a production cylinder head that was over the top with improved water jacket restriction to eliminate hot spots and detonation. They also paid special attention to intake and exhaust runners, bowl design, valveguide interference, valve design, and a host of other areas to make the RHS head a casting you could literally bolt on right out of the box without modifications. This comes from better CNC technology, which yields matched components you don't have to worry about when you're building an engine. Call it Power by Design.

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Aluminum Pro Action Heads
RHS Part No.Intake Runner & Chamber SizeValve Size Int/ExhApplicationPower Expected
35001180 cc/64 cc2.02 in/1.60 in302/351 ci
Street
325-400 hp
1,500-6,500 rpm
35002200 cc/64 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35003215 cc/64 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm
35004180 cc/58 cc2.02 in/1.60 in302/351 ci
Street
325-400 hp
1,500-6,500 rpm
35005200 cc/58 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35006215 cc/58 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm

Cast Iron Pro Action Heads
RHS Part No.Intake Runner & Chamber SizeValve Size Int/ExhApplicationPower Expected
35301180 cc/64 cc2.02 in/1.60 in302/351 ci
325-400 hp
1,500-6,500 rpm
35302200 cc/64 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35303215 cc/64 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm
35304180 cc/58 cc2.02 in/1.60 in302/351 ci
Street
325-400 hp
1,500-6,500 rpm
35305200 cc/58 cc2.02 in/1.60 in302/351 ci
High RPM
Street/Race
400-550 hp
3,500-8,000 rpm
35306215 cc/58 cc2.08 in/1.60 in347-421 ci
High RPM
Race Only
550-650 hp
4,500-8,500 rpm

As you can see, RHS has a wide variety of cylinder heads for small-block Fords. Expected horsepower, according to RHS, is the same with aluminum and cast iron. However, it is our belief horsepower numbers will be lower with cast-iron heads because they don't have the same kind of heat transfer as aluminum heads. As a result, horsepower won't be as high. Cast-iron heads are also heavier than their aluminum counterparts.

Flow Bench
RHS shipped three Pro Action cylinder head castings to Westech in Southern California for us to demonstrate how these heads flow right out of the box. Here are the results as based on a 4.030-inch bore.

180cc Air Flow Specifications
Valve LiftIntake Flow in CFMExhaust Flow in CFM
.050 in23.420.0
.100 in55.648.0
.200 in111.098.0
.300 in158.0133.0
.400 in206.0170.0
.500 in240.0189.0
.600 in252.0198.0
.700 in260.0203.0

200cc Air Flow Specifications
Valve LiftIntake Flow in CFMExhaust Flow in CFM
.050 in31.523.0
.100 in63.050.0
.200 in119.0104.0
.300 in172.0140.0
.400 in216.0174.0
.500 in244.0193.0
.600 in264.0203.0
.700 in275.0209.0

215cc Air Flow Specifications
Valve LiftIntake Flow in CFMExhaust Flow in CFM
.050 in26.524.0
.100 in60.052.0
.200 in116.0102.0
.300 in168.0134.0
.400 in217.0172.0
.500 in260.0181.0
.600 in292.0190.0
.700 in305.0200.0