Best Torque Delivery

[Robrover]

I'm looking at replacing the 4.6 in my SD1 with one of Triumph Rover Spares 5.0 litre blocks which use 96mm Top Hat liners. I'll swap the big valve Buick 300 heads onto this and raise the compression from the current 9.25:1 to 10:1 at the same time. The Edelbrock and Crane cam will stay.

The outgoing almost new 4.6 block (9.35cr) which has only done a couple of thousand km in the SD1, will be going into my 3.9 Disco using the existing heads and front cover plus a high torque cam. The hot wire 14CUX (Oz spec, no cats) will be retained but will be adjusted using the Unichip interceptor module to provide the extra fuelling needed. I'm looking at developing around 240 -260 bhp, but with 300+ ftlb of torque which is what's important in shifting a heavy 4x4. With this in mind what should / shouldn't I be doing to the heads; presumably big ports and valves are out? And which cam is recommended, RP4, RS Stump Puller, Lund LE1, JE101?