I've got a VR manual harness in my VH, VR K-frame and VS steering rack
I just used the VH tie rod ends, and a VL intermediate steering shaft to adapt the VS rack onto the VH steering shaft
I have Pacemaker headers, but the VR manifolds will fit fine. Exhaust shop will be able to modify your exhaust system to fit the manifolds as the outlets will be in a slightly different position to the VH ones.
If you look carefully at firewall (engine bay side) just above the passenger side chassis rail there should be a dimple. If you drill your wiring harness grommet hole in that location it won't foul with anything inside the cabin. I have A/C in mine and it's a close fit, but it fits.
Tailshaft may need modifying if you are running the T700 or T5. It's usually easiest just to swap the front half of the VR shaft onto the VH shaft, ensuring you maintain the correct phasing (ie front uni position in relation to the rear). I'd also highly recommend getting the tailshaft balanced after that.
You'll need an adapter rear crossmember for the gearbox. You can either make your own or buy one from the likes of American Autos, Castlemaine Rodshop or Dellow