Starting a brand new 61 inverted on the airplane sounds like alot of fun . The best approch would be to remove it and run it in on the bench. Otherwise set the plane in a cradle upside down so the engine can be started upright. A heat gun on the head will make it less tight so the poor tower starter has a chance to turn it over. You will have alot more luck starting it like this for at least the first flight of the day.