That's a 48" cast center deck. Possibly built between 1968 and 1971.
You may be able to download this PDF, it has a lot of information in it.
http://www.onlycubcadets.net/forum/s...ad.php?t=24721
It has also been difficult for me to find information on mower decks based on the ID tags. The first two numbers on the tags are the deck size.
You must have done something REALLY bad if the manuals section gives you a permission denied!