Slight Rattle or Knock?

When my car warms up there is a slight rattle or knock, sounds like it is coming from the top of the engine, maybe valve train or something like that?? I know it is virtually impossible to diagnose this without hearing the car but the motor is stock with very minor mods and it has barely 80,000 miles on it. Also has been babied most of it's life. Any help appreciated, want to take it to MOTOR MAGIC this weekend and want to figure out if it is safe to drive. I will take it to a mechanic today as well.

oh that's not good, is there any way of knowing for sure or am I better to get a mechanic to look at it, or are they gonna just guess what the problem is? guess I will have to make a decision to gamble or to not gamble.