THE LPG tank is generally mounted under the Territory where the spare wheel is. The spare is then mounted on the side in the back of the cabin. That's no problem for a five-seater, but it does present a problem for a seven-seater. You really need a swing-away spare wheel mounting to hang the spare on the rear. Phone the offroad specialists who might be able to supply you with an appropriate bracket. There shouldn't be any issue with the engine, but be aware Ford doesn't recommend converting its cars and your warranty will be affected.