It's probably a Trick Flow 3 cam. Which I have a spare, if anyone wants one. That's the exact lift for a Trick Flow 3 cam. It would make sense, because it had Trick Flow heads on it, and someone thought they were smart by putting a Trick Flow cam with Trick Flow heads. Unfortunately, that cam is ground for the big Trick Flow 205cc Twisted Wedge R heads.
Not going to hit 500 crank hp without a power adder. Those heads are nice, but they are just too small. I wouldn't worry about trying to make 500 crank hp N/A. You got a nice engine there, just swap out the cam. Making 500 crank hp is going to mean redoing the whole engine. More compression, bigger heads, and all that noise. I wouldn't bother redoing the whole bottom end to make it a 347. There wouldn't be a whole lot more power gain with the extra .15" stroke.
I'd get a custom ground cam, and have some fun. Check the valve springs on the heads while you are at it. If it had the valve springs that came with those heads, the cam probably tore them up. I'd change them and the cam. It'll make the car nicer to drive too.
Kurt