ok i decided my car is ticking like a time bomb waiting to do what the last engine did (KABOOOM

) ill post some pics of that when i finish taking it apart, may get a kick out of it, or cry.
any thing in particular when rebuilding the head? like valve scores or piston wall gouges(when i got the head off), and should i replace all the valves and springs and retainer clips or just one's that need it? as well as the gaskets. any tips on the spring tension measurements. should i replace the timing belts since ill have the cover off, and not knowing when it was done last?
i think i seen a post of caming but too many pages down to remember. is caming a good idea or waist of time like the K&N air filters, does it all depend on how much to cam. is there much power gain? or a link to caming discusion.
thanks agian