I have a Mark VII GT-500 in a 14' wide bay. You could put in pretty much any length bay, but it may not wash the rear of very long vehicles. My bay is 34'6" long. I can wash my crew cab short bed F-250 in it. I must be right on the limit as far as length because sometimes it will wash correctly and sometimes it will throw a "vehicle too long" code and not tilt to wash the rear. IIRC, they have a kit that will make it a "short bay" machine. I don't know what the kit consists of or how much length it will gain.