Auto Racing: Mazda Cams, mazda b2000, rear gear ratio

Question
I am looking into installing a Camshaft upgrade into my Mazda b2000.  The two choices I have are 260 and 272 Duration.  I do not know what "duration" means or which cam is better suited for me or my vehicle.  Can you please tell me what "duration" means and the different applications they can be applied to. Also, am I any further ahead installing one of these cams than my stock cam?  

Thank You,
Matt

Answer
Hi Matt. This is a very important choice to make ,it's probably the most important parameter in a cam choice .duration refers to the number of degrees of rotation that the intake or exhaust valve remains open to allow fuel and air in or burnt gasses out. the higher the duration number on the intake side especially the higher up in the rpm range peak power occurs  at the expense of low rpm driveability ,too much duration can make the vehicle nearly undriveable .the correct choice can really wake a vehicle up . there are several factors to consider one is emmission legality,transmission type (automatics may need a torque converter change ).type of induction(EFI,carb )rear gear ratio ,etc. a call to a cam company tech line will get you the correct cam .Good luck with that hauler! jMazio.