Now you're allowed 183 days in a 365 day period and the fine for overstaying is $5 a day. Now whether or not this law will be enforced is a totally different matter. You can read all 18 pages of the law at El Peruano. I personally think it's about time that Peru is making their laws stricter. A tourist shouldn't be allowed to overstay their visa by years and then come back right away.
NB: I'll be taking a break from blogging at The Ultimate Peru List in March. While I'm gone you can take a look at my other blogs. New posts will be published starting in April.