I'm looking to buy some new heads for my car and think I've settled on Afr 165s. I'm just wondering what to expect in horsepower gains? I would like to be close to 400hp. I have an Edlebrock performer intake, 600cfm carb, Bbk Longtube headers, no cats, and a small cam slightly bigger than stock. Do you think this is a realistic expectation? Do you think it's worth it? Thanks for the advice!