Re: long runner intake manifold
The manifold on your XH is not that long.
When I put the BBM manifold on my XH I did the measurments and the standard manifold is the same length as the short runners on the BBM. The long runners on the BBM were around twice as long.
Dyno runs proved it by showing no improvement in the top end, only the bottom end when converted to BBM.
4L I6, naturally aspirated producing 173.5rwkw.
14.410 @ 96.49mph with street radials.
What's that?..... Did I hear you say TQE power?