hi i have a 428 motor, right now it has a RV cam, small duration and lift, d2teaa heads, ( wich im gona get ported ) and a preformer intake, 750 edlbrock carb, and a few other odds and ends. what im getting at here is will a 280H magnum cam work with my heads?? or do i have to get the whole get and get new valve springs, and lifters etc? please let me know thankyou