is it worth installing cam in stock 318?

Hello

With money being tight right now does this plan make sense to do. Car is 70 dart 4 speed 3.55 gears. Stock 318 small valve heads, stock exhaust manifolds. we have an edelbrock performer manifold and 600cfm carb and dual exhaust on it now. Question is, until we can do something with another motor, would it help much to install a small cam like a lunati 60400 , or small comp hi energy, or the like. Of course including the correct springs, new timing set, etc. What kind of improvement could we expect?

thanks