I've still got my 1.4 Tbird. I can't even get mine up to 1500 stable (even at 1.85V), so right now I'm running mine at 10x143. Another part of my problem with overclocking this thing is I have cheap Best Buy PC133 RAM that is keeping me from upping the FSB anymore.
The nice thing about the 1.4 is I think all of them are multiplier unlocked, so if you've got the memory, you can really run the FSB up high without pushing the chip too far. In general though the 1.4 Tbirds were not known for great overclocking.