Of course the Dellortto manifold and a set of Jenvey bodies as well would be better if ultimate performance is your aim  - but not much change out of a grand before you even think about the rest of the kit..  The Rover bodies are almost a direct swap for the Strombergs and are dirt cheap. I recon you could have the whole lot up and running for about £300 using second hand parts.  Modern fueling, modern ignition and the joy of DIY.  You might even be able to use the standard air box so it all looks almost original.

If you're running a Magnum single carb only one body would be necessary so even easier.  Use the standard glass top pump to lift up to the swirl tank mounted down by the rad on the drivers side and a high pressure pump and lines to the fuel rail, hey presto plumbing sorted!

You can get injector mounts from various sources and they can be Lumiwelded to the manifold.  The injectors on the XE fuel rail are virtually the same spacing as the slant 4 manifold and again hey presto injectors sorted.

Dave Walker wrote a superb book on Engine Management published by Haynes and it is a must for anyone wishing to experiment with any thing electronic.