Cylinder Heads & Intake Manifolds

Head Porting

Hi my name is Don Terrill and I host a show called Speed Talk where we get the best technical minds in racing to share their knowledge. This is not your typical fan based show, this is for the hardcore racer.

People were always asking me for my list of favorite interviews. Well, we decided to put together a Best of Speed Talk Series and you're going to be blown away when you see the experts we've compiled for you on the subject of airflow - It wasn't easy. Phil Martin (Head Porter at Richard Childress Racing RCR) was on the show, but only through some incredible luck. Now, NASCAR teams are not about to let one of their employees come on the show and spill the beans, but Phil just happened to between jobs for one week and they couldn't stop him.

These guys didn't hold back either, they answered ever question I had. For example, Phil said after listening to his interview, "I probably said too much." and Darin Morgan (Head of cylinder head development at Reher Morrison) believes that by sharing what he knows with others he will greatly accelerate his own learning curve.

Not only did we get heavy-hitters in NASCAR and NHRA, but we also got Jim McFarland (VP of R&D at Edelbrock for 20 years), Harold Better (Senior Vice President at SuperFlow) and Joe Mondello (Professor of the only Porting School in the country). The final four interviews are with Tom Kolimatsis (TK Race Heads), Peter Hill (Pro-Topline Cylinder Heads), Audie Thomas (Audie Tech) and Rick Miller (Extrude Hone).

What questions did we ask? Check out the long list of subjects covered below. No fluff, just hardcore technical.

Also, for the past few months we've been sending out pre-release copies to industry professionals and customers for review - we've posted some of feedback below.

Thanks for stopping by,
don terrill
Host of Speed Talk & Publisher here at

Phil Martin - Richard Childress Racing - RCR
Phil has been porting heads and intakes in NASCAR for 15 years and we had some real luck getting him on the show. Nascar teams are not about to let their employees come on and give up their secrets - luckily, there was a one week window where Phil was between jobs and we got him.
Darin Morgan - Reher Morrison
Darin (Head of cylinder head development at Reher Morrison) was a real joy to interview. With his motto being "There are no secrets", there's no question he won't answer. Darin gives quite a few formulas for calculating port dimensions.
Jim McFarland - Edelbrock
Jim McFarland is a true legend in the industry - it seems like he's done it all. Here's just a few; publisher at Hot Rod magazine, VP of R&D at Edelbrock for 20 years and the engineering consultant at Hedman Headers.
Harold Bettes - Power Technology Consultants
Harold is a former SuperFlow VP, and after talking to him I realize, an airflow junky. He has been closely involved with two very exciting events, the Advanced Engine Technology Conference and the Engine Masters Challenge.
Joe Mondello - Mondello Performance
Joe Mondello is owner of the Mondello Technical School & professor of it's porting class. Chevrolet performance cylinder heads still utilize the identical combustion chamber, which Joe designed in the early 1960's known as the "Posi-Flow" chamber.
Tom Kolimatsis - TK Race Heads
Tom is the owner of TK Race Heads in Laval QC, Canada. He has over 23 years of experience and 14 NHRA Drag racing world records. Tom also has a strong understanding of 4 valve heads.
Peter Hill - Pro-Topline Cylinder Heads
Peter is the international sales & marketing manager for ProTopline Cylinder Heads. Don't let the title fool you, he's got a great technical understanding of airflow.
Audie Thomas - Audie Tech
Audie is the owner of Audie Technology. They manufacture airflow and camshaft testing equipment. Audie created the data acquisition and control for a custom wet flow bench now in use at Dart Machinery.
Rick Miller - Extrude Hone
Rick is the head of the performance department at Extrude Hone. They have a very unique method for airflow improvement You may think you know every possible use of their service, but I think you'll be surprised by one that NASCAR teams are using.



  • What are your core beliefs on air flow?
  • How do you get the most out of a head?
  • How do you shape the all important short turn?
  • How would you design a port from scratch?
  • How do you calculate the following?
    • Valve size needed
    • Port size needed
    • Window size needed
    • Bowl size needed
    • Seat ring ID needed
  • Where are the biggest airflow restrictions?
  • Differences in porting the intake port and exhaust port?
  • Take us through the steps you take when porting a head.
  • What are your favorite airflow formulas?
  • How does porting a four valve head differ from a two valve?
  • Air Flow Testing Tools:
    • Flowbench - Best? Cheapest? Building your own?
    • Diagnostic tools (flow balls, pressure probe, velocity probe, etc)
    • Getting accurate results
    • Duplicating your work (Templates, gauges, et)
  • Modifications - Area Specific:
    • Gasket - Area? Shape? Height?
    • Pushrod - Area? Width?
    • Roof - Width? Tip? Angle?
    • Floor - Width? Tip? Shape?
    • Walls - Shape?
    • Window - Area? Shape?
    • Short turn - Height? Width? Corners? Radius?
    • Bowl - Width side to side? Width front to back? Depth? Shape?
    • Guide - Shape? Height?
    • Seat - Shape? Transition to bowl?
    • Combustion chamber - Squish side? spark plug side? valve shrouding? Shape?
  • Valves:
    • Diameter - How do you decide?
    • Face - Angle? (45', 55', etc) Width?
    • Back cut - Angle(s)? Width?
    • Shape? (Nail, Tulip, etc)
  • Fixing flow problems:
    • Poor low lift - What areas to focus?
    • Poor mid lift - What areas to focus?
    • Poor high lift - What areas to focus?
    • CFM backs up at upper lifts - What areas to focus?
    • Turbulent (noisy) - What areas to focus?
  • Reverse flow - How to test? What to do?
  • Swirl - What is it and how do we use it to improve power. You might be surprised by his answer
  • Epoxy - When to use?
  • Welding - When to use?
  • How to get the most out of engine simulation software
  • I hear Winston Cup teams are using Extrude Hone in a different way, what are they doing? This was a real eye opener.
  • The biggest head porting mistakes you've seen?
  • Current trends in porting?
  • Biggest discoveries you’ve made working on cylinder heads?


  • Tell us about the different manifold designs, and the advantages/disadvantages of each.
  • Give racers advice on picking the right manifold.
  • How to design a manifold from scratch.
  • Manifold Porting: How do you decide size and shape? How do you do the modification? Let's look at each part of the intake and get your thoughts.
    • Carb Flange
    • Plenum
    • Dividers
    • Runner entrance (at plenum)
    • Runner roof
    • Runner floor
    • Runner walls
    • Runner exit (at gasket)
  • What are your thoughts on fuel distribution?
  • What are your favorite formulas relating to intake manifolds?
  • What are the latest trends in manifold design?
  • What are the latest trends in manifold porting and modification?
  • What are the biggest mistakes people make when it comes to manifolds?
  • Biggest discoveries you’ve made working on intake manifolds?

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Customer Comments:

    "Buy this set of interviews. Reading between the lines has allowed me to think "out of the box" on a couple of tangents and we shall see. is THE HARDCORE site for Performance."
    Chris Straub - Stef's Performance / B&B Performance
    Lakewood, NJ

    "Being a Cylinder Head Porter, I especially enjoyed the interviews with Darin Morgan, Joe Mondello, Jim McFarland and Harold Bettes. I wear headphones while porting heads, and enjoy listening!"
    Larry Meaux - Meaux Racing Heads
    Abbeville, LA

    "Interviews are great and provide information not readily available. As a professional engine builder and "information junkie" I find all of this very refreshing. Keep up the good work."
    Mike Thompson - Brodix Inc.
    Mena, Arkansas

    "I enjoyed it. It's a good thing that you guys can do this kind of research for me"
    Paul Melanson
    Denver, CO

    "After listening to the interview with Darin Morgan I have realized there is much more to learn in regards to the art and science of induction system design from carburetor to muffler. Thanks guys for the thought provoking information."
    Dwight Hall
    Tampa, FL

BONUS INTERVIEWS: (Included for a limited time)

  1. Mike Chapman - Charge Motion Porting
  2. Barry Grant - Carburetor Tuning
  3. Larry Widmer - Induction Dynamics
  4. Mark Lacy - CNC Porting
  5. Mark Lelchook - Header Technology

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Package Deal:
Airflow Experts plus Engine Experts Regular $198 - Today only $97- Add to Cart

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