[dave in australia]

I'd follow Mitch's method. Plugs in, remove head nuts. and wind over without turning ignition on. The problem with using a metal scraper is that you can scar the deck or the head without realising it until it's too late. I've used wood wedges on engines that are sitting under the bench with success as well. Also try some penetrene or mouse milk around the studs the day before to help free things up. Try a hot air gun on the head near the distributer after applying some penetrating fluid.