If you hang around cars long enough, you'll come to realize that there are no genuinely new ideas. But given the nature of car crafters and their ability to get engines to leap tall buildings in a single bound, it was only a matter of time before somebody came up with a better Mousetrap.
At first, everyone thought that bigger was better, but the Boss 302 heads proved that size wasn't the key-it was a combination of intake and exhaust flow and mixture velocity. Then we got into valve angles and port shapes. But Jon Kaase thought he had a better idea.
Kaase (pronounced KAH-zee) has been playing with engines, drag racing, and making horsepower his whole life. His big break came in the late '70s when he became Dyno Don Nicholson's Pro Stock Ford crew chief, and with that knowledge has created his own engine-building facility in Winder, Georgia. So he combined the best concept of the Cleveland and NASCAR Yates head with the Windsor to increase the airflow with a decent-sized intake port, and offer it up to the world exclusively through Jeg's.
Valve angle plays a big role in port flow for several reasons. First, air and fuel do not like to turn corners, so if you can angle the valve so that change of direction is less abrupt, you can improve flow. Second, and perhaps just as important, the position of the valve relative to the cylinder is also crucial to flow. Many cylinder heads attempt to improve flow by stuffing in larger valves, which means the intake valves move closer to both the chamber and cylinder walls, which hurts flow since the air and fuel moving out from between the valve and the seat is restricted. Flow usually improves with a larger valve, but not as much as it would be if the valve was less restricted.
But when you move valve angles and positions, it's easy to create valvetrain geometry difficulties that require a prohibitively expensive shaft rocker system, or perhaps you end up with a stud-mounted rocker system that suffers from premature valvetrain wear. Kaase knew that this new head had to remain within the stock intake and exhaust port position limitations as well as maintain the stock stud-mounted rocker arm valvetrain. With all those limitations on the design, he went to work experimenting with several variations before arriving at this final design.
If you look at the photo of the valvetrain from the intake side, you can see how Kaase has canted the valves inboard. This angles the intake valve away from both the chamber and cylinder walls to increase flow, especially at the higher valve lifts. But Kaase didn't stop there. In addition to changing the valve angle, he also moved the intake valve toward the center of the cylinder, which also contributes to increased flow.
One of the best ways to evaluate this head is to bolt it to a Superflow 600 flow bench and see just what numbers it generates. We should point out that in order to get this story as soon as possible, we chose not to wait for a true production head. This head is somewhere in between the original prototype and a production head, but Kaase has assured us that it is representative in terms of intake and exhaust port flow.
One way enthusiasts compare cylinder heads is by the intake port volume. It may appear at first that this is an amazingly large intake port with a volume of 247 cc's. This compares to a typical mild performance Windsor head of more like 170 cc's, but this large port volume figure can be misleading. By changing both the intake valve angle and position, this tended to increase the intake port's bowl volume.