i realize that timing chain will never be as acurate as a gear drive setup,other than noise,what is the downside to a gear drive setup?does high rpm's have a adverse effect on gear drive setups?any other down side to a gear drive?  

Mostly more harmonics through the valvetrain with the gear drive. This can affect valve springs and even make the needle and seats in the carb open and close. This was proven by Garley Daniels and Grumpy Jenkins. Also if you have a knock sensor it will put you computer into limp mode.