Be real careful bro. I had maxed out at 180 (4 plates) for 3 and one day tore the costal cartilige where one of the ribs joins the sternum. to make things worse, the injury threw my whole upper girdle out of balance and my rotator cuffs started to get impinged a few weeks later. It took nearly a year before I could bench again, it was awful...
3 years later and I just started doing weighted dips again, and I am so freakin' happy because they're one of my favorite exercises. I keep the reps high, around 8-10.
One word of advice, if you do go super-heavy, warm up thoroughly and dont go past parallel, the deep stretch with that much weight might end up putting you out of commission.