cams and numbers?
 

can some ppl please break this down for me.. i do not understand how cams work.. i know what they are and the purpose of it is..

but i do not understand when upgarding cams what do u look for?? ..

how can i tell which ones are good for street and which are good for the track??

cam store the energy is expansion stroke and revert it back in compression stroke cam is connected with the cam shaft.