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CNC PORTED HEADS

FORD 5.0 heads

CNC CYLINDER HEAD PORTING

CNC head porting by RCS (RCS/AMS Race Car Service of America), a method of machining the intake, exhaust ports and combustion chambers of an Automotive Cylinder Head. The purpose of this is to decrease the time it takes and to increase the accuracy in machining from port to port and cylinder to cylinder. Experienced professional cylinder head porters in the past and still today hand grind and shape the intake, exhaust ports and combustion chambers. The reasons, to increase the air flow rates traveling through the cylinder head, resulting in port increase size and shape changes. The increase of air that travels through the ports is the largest reason for Horse Power gains in the automotive combustion engine. The Automotive engine can be looked at as an inefficient air pump, increase the pumps air intake efficiency and you will increase the engines power out put when all is relative, as a rule of thumb for every 10% increase of air flow you can see a 10% increase of power out put. Hand porting can take hundreds and hundreds of man hours and the ability to be consistent from port to port is were the skilled hand porter works the hardest for each port must match in flow values both at peak and low lift flow rates, as well as port volume. A good head ported can make each port flow the same flow rates, at the same valve opening, in all the ports making them equal, but this can take hundreds of hours and is very hard work. This is why CNC Head Porting has become so popular in the racing industry and now is becoming popular with the street performance enthusiast as well. Understand this, you must still modify the existing ports of the cylinder head by hand and this still requires a great head porter that understands how air works.

Just because someone has cast a head out of aluminum or cast iron doesn't mean that it is a good head. Just because a head is CNC  ported, this does not mean that it's a good cylinder head, either by hand or by CNC both can be good or bad. You have to copy (digitize) a hand ported port to create a CNC machined port, so if the hand ported port is not good, then the CNC port will also not be good. Purchase your CNC or hand ported heads from a company that builds custom engines, all different types of engines for they understand flow and port volume relations that is required to build fast running street and race track engines.

Once this is accomplished a CNC programmer and operator that does CNC cylinder head porting can digitize the surface and shape of this port and create a computer file that then can be used in CNC machining and cut this exact shape and duplicate it over and over within .0002 repeatability. At RCS we have designed and made our own computer added multi axis movement head fixtures for just this purpose. I have been porting heads for over 25 years and have ported just about every head on the street and heads used in the Performance Industry and have dyno tested each combination, hundreds of man hours in each combination to perfect what each custom wants.

At RCS the knowledge never leaves us, for we have CNC Programs for just about every popular head in the industry and if we don't we'll make one. For the advance engine shops this technology is going to become available from RCS as a CNC Porting package, including Fixtures, Tooling, Computers, Programs and CNC Machines for the shops that want to do their own machining, Call for this information.

USING OEM CYLINDER HEADS

The most common type of cylinder heads that are CNC ported is the newer style performance casting's for the hard core Performance Race Engines. The most popular styles of cylinder heads ported in the average Performance Engine Machine shops are the standard OEM style heads (Original Equipment). This has been a popular trend at RCS also for years and has been our success porting theses heads for 25 years. Our customers know we can port their heads, the head(s) on their current engine. For example, your 5.0 Ford Mustang with OEM cast iron heads, these cylinder heads can be modified to make over 500 hp with hand porting in our engine shop, but when treated as a street performance head, can give a quick 100 hp with an enormous amount of acceleration, which is what a street performance engine must have. You will also need to do a camshaft design change with a slightly larger duration. By using the castings you currently own, lowers the cost of the performance head(s) by 50%, not to mention the port volumes are smaller on the OEM castings, which will increase the acceleration of the engine. Large volume intake ports KILLLLLLL!!! Accelerating HP in all engines, but more so in smaller engines or engines that are engineered to be driven on the street in need of a wider power band. What you feel when setting in the drivers seat of your car, hard on the throttle, is accelerating horse power not steady state Dynamometer tested horse power, this is a power that can not be measured on an Engine Dynamometer or Chassis Dynamometer, this is measured by time over distance like being at a 1/8 or 1/4 mile Drag Racing Track.

The reason you do not see head porters CNC porting cast iron is that the ports are to small and the work that is required to program these small ports is to hard, plus the heads are cast iron, very hard to machine with any speed, hard on cutters and they can't make enough profit. If you notice every body is selling the same thing, after market aluminum cylinder heads, every shape and form, good or bad. A cylinder head caster or most high volume cylinder head companies are not true engine builders and lack the many years experience (knowledge) that the street or street-race engines require. They do not understand the intake manifold system or fuel system that you have and don't care for they are selling air flow numbers, When's the last time you saw anyone race a flow bench or win with a dyno? We don't race or drive flow benches or dyno's!!! They are measuring equipment and not what the car wants to make it accelerate fast.

A quick Story;

1972 Camaro, 413 HP, 446 ft trq - 406 s/b Chevy with a dual plan Performer intake and 750 cfm vacuum secondary carb, 3 speed Automatic with 2,400 stall, 3.73 gears, Hi flow exhaust, 8" wide tires in the rear. This car should really run and spin the tires for ever? We dynoed this engine, we built years ago when we were learning, we read magazines and performance tips from all the different companies like GM in the past as we were growing. We no longer read performance magazines or take anyone advise anymore, for most don't know what the hell is going on (opinions). GM states in there performance books and many others and sells a dual plane intake with the divider lower 1 inch for increase power. Again I state "we do not drive dyno's". This engine was short by 3 hp from making 400HP and the customer wanted 400 plus. We removed the intake and machined the divider lowered to 1" x 2.5", reinstalled the intake set everything and we made 413 HP Great, the customers happy, we're happy. We install the engine and road test the car, we're happy, but not impressed, the car had no hard charging low end power, twenty feet out it ran like a rabbit, but only spin the tires about 10 ft, when you really launched the car hard. We worked with the vacuum secondary, discharge nozzles, everything, to try to get the car to launch harder, we gave the car to the customer and soon the customer returned, quote,

"I'm not happy" That was the last time I ever heard a custom say that to me again!!!!

The car doesn't spin the tires enough and I want the car to spin the tires. No problem I said, We then removed the intake manifold and welded up the divider and reinstall it. Our property frontage is over 100 ft long, From one end to the other the tires were smoking, through first and second hang on what a ride. Don't believe everything you read, even from GM. The jest of this story is that, the engine dyno, flow bench are only tools for measuring and are not to replace experience and track testing. Air volume under the carb in the intake was to big, combining the two sides together, slowed down the air velocity at slow speeds to much the end result, starving the cylinders of air and fuel.

We have learned over the years that all the cylinder heads sold in after market, the port volumes are to big, Why? Anyone can make a large port flow air and air flow numbers is what they are selling. If your engine could talk, it will tell you smaller, I want my ports smaller. Believe me your engine can speak, but in another way, it just doesn't make any power, read the signs, where does your engine come alive, what part of the power band.

The problem with Performance After Market and some early OEM cylinder heads is that their port volumes are too large for the amount of airflow that they flow. This becomes a problem for the street performance engines and makes a lot of customers that purchase heads or engine parts through Mail Order companies very unhappy. Acceleration is what we are looking for, settle for nothing less when designing an engine. This is the black art of engine design for with acceleration comes, fuel economy, throttle response, faster 0-60 MPH speeds, cleaner burning combustion and higher Dynamometer tested power. This is what good Performance Engine Builder push to achieve. This can be achieved through Mail Order business only if you are either lucky, you have found a salesman that has experience and or you can copy what has been already designed. The problem with Mail Order is that if the part doesn't work for you, you used it, you can't return it and the funds you allocated for your project is now spent and your stuck with the out come. Performance Magazines can also be miss leading if the information is made to impress the public and sell magazines and produces, most magazine companies do not represent or support the information they print.

WHAT CAN YOU EXPECT FROM CAST IRON CYLINDER HEADS?

There are cylinders heads from the OEM industry that make great horsepower when prepared by an expert head porter. RCS has ported OEM cast iron HEADS for engines that have made up to;

We know this for we Dyno tested each of these combinations. This does not mean that these are the highest possible power values just where we have been. These were all cast iron cylinder heads from your factory style engine that were all drove off the show room floor. Most of these OEM castings are cast iron and cost a little more to port, because of cast iron. The option of CNC porting these cast iron beauties is growing. Aluminum is the most popular request and most serious race engines owners want because of the difference of weight, reparability and new technology, but Cast Iron vs. Aluminum, Cast Iron Heads will yield more Horse Power when comparing two equal heads, that's a fact. When you have a budget and already own one of these greats you can have a wonderful amount of power, enough to turn anyone's head at the track. The option of maximizing out your heads is not always necessary for you can make all levels of power from these beauties. See anyone can pick up the phone and buy a mail order aftermarket head and be just like a lot of the other people out there, but blow your friends mine when your OEM sleeper kicks there butt. Good luck!

RCS also sells all the cylinders heads in the industry and can port any cylinder head in the industry to match the customers needs.

MAIL ORDER CYLINDER HEADS

Not all cylinder heads are equal, just like not all mines are equal, why would a person by a cylinder head

from a company that only brokers Cylinder Heads and does not specialize in using them on Engines that they

build and sell. For there are only a few companies that make Cylinder Heads, the rest are brokers of the

industry. The company selling Heads must truly understand what is needed from the cylinder head when

choosing for the complete engine requirements, one must look for a company that does both, Cylinder Head

and Engine assembly together. From the customers view point the real test and answers come from putting

the heads on and testing them yourself, at your own expense, there's no returning them if your not happy or

if the power band is poor at low speeds and the car lacks accelerating HP and now requires 4.10 gears to

make the car perform. The more accelerating power an engine makes the less gear is required, think of this,

some Pro Stock Drag Racers us a 3.90 rear axle gear to go over 215 miles per hour in the quarter mile.

Cylinder Heads are the most important part along with the correct camshaft when building the power band

of your engine. This is an area of the engine that a customer or engine builder should not over look or take for

granted to be adequate. Some engines that have lower engine power on the Dyno have great accelerating horse

power due to the correct intake manifold, cylinder head port volumes and camshaft, not cylinder head

advertised flow rates. Price should not dictate your decision when choosing a cylinder head, the more time

and parts that go into a project warrants a higher price, every shop works almost at the same labor rates or

we wouldn't be able to stay in business. The cost differences come from how much work is going into

the product with the quantity and quality of parts used, which will yield a better product and performance for the customer. The reason a customer sees so many Cylinder Head Shops selling the same stuff,

Cylinder Heads are little in size, are easy to handle, can be bought from the manufacture assembled

with out any additional work required for the average and require no liability on the seller's behalf for

their intended use and require no guarantees on power out puts. Do business with cylinder head

companies that can prove the parts they sell from their personal experience and not by what is read

in a magazine. The industry is like this for there are no Engineering Standards to follow in the after

market and that is why there are so many companies that representing another companies products.

Give us a call on your Cylinder Head needs 1-888-881-1012.

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