Manky, as I recall, the tall deck block is only about 1/2" taller than your Mark IV, so look at your headers now and see if there's room for them to move up that 1/2" and still clear the starter & steering without additional modifications. Just my $0.02 without too much thought.

Have you ever posted pictures of your Camaro? We'd really like to see pictures of the steering conversion, along with some of the whole car in scenic Australia, too!!