Sounds like time to do an engine rebuild and be done with it. Have changed cam's but it is a job with in itself. When racing you do a lot with pulling cam's and changing tappets. Just wanting to get the most power we could get. Sometimes we would wipe out a lob on the cam or have tappets that would not work. You will be much better off with a fresh motor in the car and be amazed at the power you will have. Good luck.