Well darn, had the floor in my 1969 starchief all smoothed out and went to clean before installing new flooring and found a new bubble about 5 inches around just in front of where the driver seat pedestal was mounted. So now I think it is best to replace the plywood floor The one that is in there looks to be a 3/4 inch ply with a1/2 inch ply over that. Is that common? I have read of people using just 3/4 inch. Can anyone tell me what was original? the two sheets were glued very well before they were installed. I could get pictures if that would help. Either way I am replacing it.