Should I keep these heads?

I don't think you'll have to cut up the cars metal in order to install headers. True, there are some model headers that would require that, but there are more that do not require it.

Best of the bunch are ethier Dougs or TTI headers. Both expensive but worth it.

Stick with a zero deck piston. I'm not sure what cam would do the trick for 13's. I'll have to do some figurin before I suggest a cam.