What does the stock market have to do with small block Ford cylinder heads? Not much unless you ask Tony Mamo, the principal port designer of Air Flow Research cylinder heads. The former Wall Street stock broker by day and cylinder head porter by night told us, "Rather than researching investment opportunities for my clients I was spending my free time building my ten-second Monte Carlo.” Knowing cylinder heads are the key to building huge power Tony decided to build his own flowbench to quantify and guide him in the search for more airflow. “I became obsessed with airflow and working on the flowbench.” Burnt out on the high anxiety broker lifestyle, and coming to terms with the fact his talents and passion weren’t located on Wall St., Mamo made a final trade, exchanging a career on the trading floor for one on the shop floor.
Tony Mamo AFR
AFR's Tony Mamo still uses the flow bench he made in 1996 to test his designs.
The self taught cylinder head porter took a job at New York’s famed Shafiroff Race Engines. In short time his cylinder head work was helping to push their Chevy motors to new power levels.

Fast forward to 2000. Air Flow Research heads are quickly becoming the aluminum head of choice for Chevy and Ford enthusiasts. The AFR plant in Pacoima, CA runs 22 hours a day, six days week, churning out 700 pairs of heads per month. They still cannot keep up with demand. New Haas CNC machines are filling up the once modestly sized Pacoima, CA facility. To keep on top the Sperlings look to bring on someone who can help with their Sales and R&D efforts. At a PRI show Sperlings meet up with Mamo, whom they'd already been familiar with through their dealings with Schafiroff. The Sperlings indicate their interest in developing a big-block Chevy head, and Mamo offers to sell them his designs. AFR goes one further and offers Mamo a full time job. As they say, the rest is history and a relationship was born. Mamo, who wears several hats in any given day as Sales Manager and R&D manager in charge of port design, wastes no time putting his real world experience to good. He looks to improve on the already efficient and powerful AFR port designs. One day while analyzing a cut away of AFR's small block Ford 165cc head Mamo notices potential areas for better flow. He approaches the Sperlings with the idea of an improved Ford head, and Rick tells him to run with it.

Improving a Great Design
The success of AFR's 165cc Ford head, now a top over three thousand engines, has been in the conservative intake runner volume and 1.90" valve diameter. Moving more air without increasing cross sectional area is an often overlooked recipe for good power while retaining impressive torque. This has been a hallmark of the 165cc head, especially amongst the 5.0L Mustang crowd. Hitting the 300 rearwheel horsepower mark from the small displacement Ford, a feat once only accomplishable by over-cammed NMRA motors, has recently become run-of-the mill thanks to the advance in aluminum aftermarket cylinder heads like the AFR 165.

With the bar already set high Mamo works to give Ford enthusiasts yet another reason to rave about AFR. He starts with the existing 165cc head and makes seemingly trivial changes with a die grinder. Each time the port is reshaped, a flow test follows to measure the effect. Even more important than removing material in the right places is being able to add material and pick up flow. Tony calls this concept "shrink porting". Improving the current 165cc head incorporated exactly that; adding material in areas he felt were "dead" or slow moving and not conducive to flow. At least one-hundred trips to the flowbench later and what we are left with is a new port design with the same volume of the original. Flow is picked up all across the lift range due to a better shaped and more efficient port design that will allow higher airspeeds before ultimately stalling. Of course the AFR heads
are not hand ported but precision cut by CNC (computerized numerical control) machines. Everything Mamo does with the finesse of a die grinder needs to be translated, and consistently reproducible by the CNC software. What may yield great results by hand is useless if the machine can't reproduce the results. Enter Guy Trip, an AFR twenty year veteran, and part owner, who heads up the Engineering department. Trip, a self taught CNC programmer, and the AFR engineering team have made huge advancements over the years in their ability to digitize and reproduce the airflow results of a port design that Mamo might have worked months on.

Making new molds in an expensive proposition. However, revising the CNC program is much more economical.
Another constraint, and perhaps the most difficult to grasp for the outsider looking, is there can be no changes to the mold. All improvements need to occur in the CNC process. It's is much more cost effective to change around a CNC cutting pattern than to developing new molds. The former can be done infinitely, with the only expense being the time it takes to make the inputs into the software program. On the other hand making a new mold and casting heads from it is a $75,000 proposition, if you go with inferior tooling. AFR typically funds $250,000 into R&D and tooling for a brand new cylinder head mold and tooling. Working the CNC end of the process makes sense as the heads really do not take shape until they get on the automated cutting machines. As raw aluminum castings they are akin to uncut diamonds - striking little resemblance to their respective finished products.

Once a new port design has been digitized, Engineering works hand in hand with R&D, flow testing and evaluating prototype cylinder heads until the end result yields airflow and volume figures within 1-2 percent of the hand-ported original it was copied from. This is no task for the impatient. Port size, locations, valve job profiles, CNC feed rates, and many other parameters all effect the finished product. The cycle of making design tweaks, engineering the CNC cuts, producing the head and testing it on the flow bench is typically a 4-8 week long process without a defined finishing line. It is a very tedious and time consuming process that must be done if you absolutely must deliver a production piece that flows at or close to a hand-ported piece that might have been “romanced” for months. Anyone with reasonable talent and access to a CNC machine can port aluminum cylinder heads, to be able to mass produce a CNC production head that truly flows big numbers across the board takes a lot of dedication and experience. One of the bigger challenges in the entire “fine tuning” process is trying to find all the airflow without increasing the runner volume. After all this still needs to be a 165cc head.

(AFR 165cc Comp Flow bench results)

In This Article:
A behind the scenes look at the development and production of AFR's new 165cc head with Competition Package.

AFR has raised the bar for aftermarket small block Ford heads with the introduction of the 165cc "Competition Porting package." The part number #1404 head benefits from an enhanced CNC porting program. The head still uses 1.90" intake and 1.60" exhaust valves.

Behind the Scenes:
The Making of an AFR Head

A Haas CNC machine performs the "First operation" whereby reference points are drilled onto the "wings". All further machining is based on these references.

Once the reference points are machined into the wings the raw castings go to a Mazack machine where the various holes are drilled and tapped and valve guides cut in.

The heads then sit in a Haas machine for the main program where the CNC porting occurs. This process is 2 hours for a standard AFR 165cc head, and 3.5 for heads with the new Competition porting package.

Once ported, the heads go on to receive a valve job, pressure testing and final assembly and packaging.
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