There is a guy in the UK, Charlie Broomfield, who writes a column for Practical Performance Car Magazine who has done something similar in mating a 27 litre meteor (i.e non supercharge merlin engine) in a rover SD1. Saw it at Goodwood last year and it was quite a sight. They used to start it up on the hour and it drew rathera large crowd.
The car now runs and has home made EFI but i believe the plan is to fit twin turbos to get the power up to 1001 bhp (1 more than the Veyron!) The current BHP is 650 so a few more than the sherman/mustang!
Attached are a couple of utube videos which are admittedly not the most exciting but give a good impression. Good noise though.
YouTube - 27 litre Rover starting up YouTube - 27 Litre Rover SD1 reversing out