this manifold for the Stage 6 head, is it extra wide so you don't need spacers when installed on a RB engine? i want to install it on a B engine but conflicting stories has me thinking it is not going to fit. i live downunder & don't want to make a mistake & order a manifold that is not for my application. i know you use a 440 manifold for this combo but this MP manifold has the cast in valley tray which will fix that issue as well. the Stage 6 heads are max wedge ports.