safe overclocking without a temp sensor?

what i have is a 9800 pro without a temp sensor. is it safe to try and overclock it without a temp sensor? even if it is, is it possible to wire one up (i'm thinking of setting up an lcd display)?

Befor the radeon 9800xt i dont think we even had temp sensors on cards and ppl have been overclocking for years, yeah its safe to overclock without a temp sensor, just stop overclocking when you get artifacts.