Dual pattern cams...Black Magic or Legit?

[DSGcoupe]

Kind of what I thought. Seemed potentially beneficial when using old cast iron intakes (read inefficient). I doubted that the gains would be enough for the headache. As stated before, I have personally had good luck just matching up the intake runners with good old fashion port work and thought. By doing this, I have never really seen any exhaust temp difference between cylinders and the plugs all looked good across the board. Guess I will stick with what I know works.

[Gaz64]

In a single 4 barrel carb engine class, ie 390 Holley, the rules could be free as far as cam timing is concerned. They run a restrictor plate, or the carbs can be measured by scrutineers.
With an oval track car that spends a lot of time at wot high rpm, it would advantageous to exploit the cam timing on the dyno for the differences between the four short intake runners versus the 4 longer runners.
Valve timing is way too complex for scrutineers, hence the rules would be more lax. They make up for it by setting strict rules for airflow. Carburetor, cylinder volume, exhaust can all be verified easily.
For a street engine, you are better off with equal intake lobes, otherwise you'll lose even more low rpm torque, just to gain a screaming top end.