I have a four post,my ceiling height is 10'-0'',the two cars are roughly 56'' (both b-bodys)to the highest point of the roof,the lift goes by 4 1/4'' lock intervals,one being right at 56'' which is to close for comfort,so the next lock position is 60 1/4'',which puts the top car right at the ceiling(again to close for comfort).Ideal situation is finding a lift that has a lock position of 57''or 58'',or if your ceiling is at least 10'-6'' or greater.To solve my problem I am going to get 12'' x 12'' by 1'' thick steel plates to put under the posts.Hope this gave some helpfull info for you.