One thing that was a hot discussion here about 20-25 years ago was that during a re-grind, you either get more valve lift however you lost valve duration time, -or visa-versa. The base circle must be reduced on the cam to increase the lift during a re-grind however at the expense of losing the time the valve is actually open. With a siamesed port, the velocity and reversion is affected, ...especially with the firing order of the Model-A/B engine where #2 and #3 cylinders are following #1 and #4.
As I recall from the discussions back then, what the various dyno results were showing was the torque band was pushed higher in the engine's RPM range when the base circle was ground smaller in diameter. Depending on your driving style and/or your vehicle's gearing ratios, having the torque band moved upward was a detriment since with overdrive transmissions and lower rear end gear ratios were being used in so-called 'Touring' engines that need power at a lower RPM to be able to pull the vehicle along without constant downshifting. In other words, it was more engine torque that was needed rather than higher-RPM horsepower when touring with overdrives and low gear ratios. This in a nutshell was why Bill came up with the new IB330 camshaft and why it became so popular over the less expensive regrinds. Again, it is all in what you want I suppose.
