Jim,
Here is something to ponder for a bit over this idle holiday week.The heads and the cam you are looking for will better serve you if you are not driven by peak lift and max flow numbers. For the remainder of this post the image below might be helpful;
The chart is comparing a flat tappet to a roller tappet profile and visually illustrates why race engine builders have a bias for roller tappet profiles. With Hydraulic roller tappets we can have access to the same breathing enhancements without the danger of premature tappet failure that plagues solid roller tappets when they are placed into day to day service as opposed to weekend race duty.
The most important range in the lift curve is between 0.100" and nearly but not max lift. The intuitive explanation for this is that the valve passes each of those points twice. It only reaches max lift once! The engine's ability to injest air is substantially enhanced by increasing area under the lift curve in that range that the valve passes through twice.
Look at the area on the graph defined by the two horizontal red lines and the corresponding red and blue lift curves. Imagine how much more lift would be required by the flat tappet cam (blue curve) to replicate the same area under the red curve — stunning is the word that comes to mind. Along with the increased lift you would also need much higher spring rate valve springs to control the valvetrain and more robust everything to take the mechanical abuse as engine speed increases.
The cam chart also tells a significant story about heads that plays out similarly to the cam story. The most important lift range for good airflow on a cylinder head is the range from 0.100" to, in this case, 0.300" (or so). Let's say your heads and cam have a safe operating valve lift of say -.550" perhaps even higher.
Get the heads flowed to find out their true airflow capacity. Lets say their peak airflow occurs at 0.550 lift. My bet is you will find 85% or so of the same flow at say 0.450" lift. This means you should be picking cams that complement your heads and heads with port profiles that provide stunning airflow from 0.100" through 0.450" lift.
If you do this you will have explosive low speed torque and power, a stunning midrange pull and a car with an overall very enjoyable driving experience that brings an electric motor like precision feel to slight movements of the gas pedal as you drive the car.
BTW the story on the 0.100" lift flow numbers is that from 0.050" and down most ports act as if the valve is closed. The begin to "wake up" shortly after 0.050" lift and are capable of (if properly ported) stunning low lift flows that substantially improve cylinder fill.
BTW the proper porting is not sewer sizing as Brent has already pointed out. The proper porting is a clean bowl behind the valve and a smooth natural rolling form from the bowl, across the seat and into the chamber. If you just port match the upper port to the intake gaskets you have achieved probably 90% maybe even more of the casting design's ultimate port flow — which is way more than you need for the kind of stuff we do,
Ed
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