Personally I plan on going with a trick flow top end kit ($2,400) and then eventually a low boost vortech kit ($2,000) at about 5 psi. That combined withe the correct fuel and spark supporting mods with full exhaust should yield a reliable 400rwhp. Of course u could substitue explorer heads/intake for cheaper but I like the TF top end.
Another good option for 400rwhp is a B&G turbo kit on a stock engine.