#5 low Compression.. Ideas?

Ran a Compression Test today wondering why the car wasnt started.. We fixed all the rockers and where getting around 190 for each. Came to the last one lucky number 5 and the most we have got was about 80. What could it be? We are going to do a leak down test tomorrow to see if its coming from the exhuast or intake or if the rings are bad.. but the engine only has about 10k on it. So it just doesnt seem right.. Anyone have some ideas

No i parked the car in Oct Cuz when i was at the track I heard something. Well it ended up being the lock on the valve for cylinder 8 and we fixed that.. but see i bought the car in june.. so we where thinking maybe it was like that when i bought it. we are doing a leak down test in the morning though