The original 8500 non-le was 275/275, but later ones were as low as 250/250. The early 8500LE were 250/250, but current ones can be at low as 166/183! Realistically, most decent ones are in the 200-250 range on both core and mem clocks. 128MB versions are typically clocked lower than 64MB (e.g. Sapphire 9100s, which are re-labelled 85000LE, are 250/230 for 64MB and 250/200 for 128MB). Retail ATI 8500LE 64MB are currently 230/230.
When you install any of the o/c tools (like Rage3D tweak which I also use), it will tell you what you current clock speeds are.