My roof is 9' from floor to ceiling and it is 8' to the garage door. Initially my garage door was mounted about 1.5+' hanging down from the ceiling on brackets. I first had the garage door mounts raised another 6" before assembling the lift. Backing the upper car in gives me more garage door clearance (hood height to garage door is about 2' and I still have about a foot to the roof) but I don't need it to park the second Pantera under it.
Measure the height of the 2 cars and add 7" for the lift ramp to check for clearance. Download the manual here which gives all the dimensions:
http://www.directlift.com/propark7.htmIf you need any other measurements or have any questions, just drop me an email. dyogi@hawaii.rr.com