Which intake manifold

Is your cam off the shelf or custom? The supplier may be able to help provide guidance on the intake. My cam (275 @ .050 bullet flat tappet) was spec’d for a peak of around 6,000 rpm by a fairly reputable builder (Ray Barton) for my exact application. Ray also spec’d my solid flat tappet in my small block and it runs exactly the number I asked for. I do agree with your cubic inches that you will have no shortage of torque but I believe the max wedge port Indy dual plane intake will make power at least to 6k.