I'm not exactly sure what you're asking. Stock heads should last a very long time as long as you keep it tuned. Make sure you have enough fuel pump and fuel injector to keep your engine fed. Going too lean will burn the engine up.
The biggest disadvantage to stock heads is that they are more restrictive than aftermarket setups. You'll see huge HP gains with new heads and s/c.
I have stock H/C/I and still dynoed over 350 to the rear wheels with a novi 2k s/c.