Most of us who have raced have had to reuse parts out of necessity. When you are strapped for cash but are still in the points hunt you are forced or tempted to do things you shouldn't. That being said I have run used cams a time or two with some results for a short until I could afford to change it out. The problem I think you might be facing is that (I assume) this is going into a street motor for which you hope will be a long time. Chances are better than 50% it won't work for you. But it is something dictated by your current circumstances.