with stock crank should i consider valve to piston clearance with a bigger cam?

 

wtf???^^^^ that is to vague a question, ptv is a result of cam timing/ valve events , not how much lift/ how big it is

 

General 112* lobe seperation,220* duration at .050", and less than .520" lift will clear a stock slug. You do not want interference so take the time to use some modeling clay and sleep well. If you have too much money do it by guess and cringe when you rev it up..if it does come off the starter.