rigth now im building a engine with 280 comp cams, i have 2 sets of spring and retainers, one is crower single springs and retainers, and ferrea dual springs and retainers...

somebody told me the singles are better for evos but idk please help what spring and retainer i have to use ! waiting reponse to finish the head !

 

You should use google and see what the rate and seat pressure of each spring is to determine which you need for the cam. Probably the ferrea duals though.

 

Ok ok.. someone told me that dual Springs break the valve stems but idk

 

you'll be fine. Springs won't brake the valve so much as a cam with a fast ramp rate can. Either way, guys run plenty aggressive cams and stiff springs on stock valves without issues.