how much horsepower from my 318?

with the cam, if i do like a .450 lift, would i have to change out the valve springs or could i keep the stock valves, rocker arms, push rods etc.??? because i believe that a stock 340 or 360 comes with a .450lift cam stock. because i'm trying to get the most power with little money. because i work at McDonalds making like 500 a month lol. yea