Depends on the power you want... what i did was put trick flows and a roller came in my 318 with the plan of later doing a 390 and using these heads on it.. kinda of spreading the cost pain out over time :) Point is.. stuff like a intake/heads can always move to a more powerful build later. I am the king of wasting money though.
P.S. you mention buying a shortblock.. if you have money just buy a complete engine from blueprint engines.. no guesswork and drop it in..