Maybe Axtell was going for peak power, trying to keep up with xr750s, and Dunstall was going for a different quality of power. I read once that Dunstall stuck with one kind of carburetor that gave a lot of control out of corners. He tried carburetors that gave more ultimate power, but they hurt lap times because his riders could not get out of turns as well with them.
With the angle the Norton intake port hits the chamber, pointing at a tangent to the wall away from the spark plug, would it be best to go with that and bias the bowl away from the spark plug to theoretically get a "whirlpool" going in the chamber?
Maybe that means one cylinder would be more efficient in the northern hemisphere of the planet, then if you rode south of the equator the natural tendency for fluids to switch rotation, like water going down the drain, would make the other cylinder better.
Bruce Crower was a bit of a British Bike nut and a thinker. In the 1970's he used to have a column in a magazine where he talked about engine theories.
He talked about spin in the combustion chamber, and how as the piston came up and made the area the mixture was swirling in smaller, that the speed it was swirling at would greatly increase, just as when a figure skater spins their speed increases as they pull their arms and legs closer to themselves, and how this sped up combustion.
Bruce converted a Triumph 650 twin into a two-stroke with a supercharger on it, just for fun.
At the lower engine speeds considered mid-range, maybe the smaller amount of air/fuel is a bit lost and mis-matched to ports made for peak power and does not have the turbulence. So making the port so it induces swirl at lower speeds and is friendly to the slower, smaller charge helps things out, makes sense, as it does that it would clip off the top.
Rick Johnson, the Honda MX superstar of decades past, once had his sponsor rig his open-class bike up with radio telemetry, back when it was a radical thing. They found that he spent very little time using all the power the bike had and WOT, the most time was spent modulating the throttle and using mid-rpms and power trying to get the power to the ground to move the bike forwards. Johnson was not even conscious of how little he had been using WOT before the results were shown to him.
In the early 1960's Edward Bilton-Smith ported the head in his 650cc Norton Manxman out according to directions supplied by P.E. Irving in his classic book Tuning For Speed, which told about hogging out the bowl of the port to bias the flow straighter down into the cylinder and away from the exhaust valve, so that the overlap of the intake and opening events would not interfere with each other as much, Bilton won a road-race championship with an engine using 100% Norton parts inside, carefully massaged, leaving the pack behind right from the start with terrific acceleration that the Norton Manx r bikes etc. he was running against did not have.
Lastly, of course Smokey Yunick said it was very important for flow(did not say anything about swirl), if possible, to get the bowl as parallel as possible with the valve stem for at least the last half-inch before the valve seat(two-valve wedge chamber). He said that a crooked bowl, if the velocity was high enough would invade the still-air cone that sat on the valve and really hurt flow. Maybe at low velocity in the mid-range you can balance things with a bowl that is crooked enough to give swirl and flow at medium velocity, but on the top end it comes back , disrupts the still-air cone and clips off the top.
Tricky stuff.
