They will not fit without modification. They do have seat tracks available finally. I ended up using chevelle tracks and modifying them. There is a sticky on one of the Nova sites that give you all the dimensions.
Finding the right seat tracks are a pain in the butt. I have a 72 which needed the high back Camaro/Firebird seats. The tracks for 68-71 Novas will fit the floorpan, but not the seats. Seems no one makes the right tracks for the high backs in a 72-74. I ended up buying an old ratted out white seat set on eBay and taking the tracks off those. Thankfully I was able to sell the seats themselves and get at least some of my money back.