AMD Athlon XP 1500+ 266MHz over/under clock

[LoTek X]

Hi everyone,
I just pulled a bit of a bonehead move. I've got an old Gigabyte 7IEX4 socket A (462) motherboard. I was interested in getting the fastest processor that the board would support which would be the Athlon XP 1500+ Palomino with a 200MHz FSB.
So off to eBay I went. I found a 1500+ for a really good price so I bid on it. This is the bonehead part- the 1500+ I bid on is the one with the 266MHz FSB.
So here's my question- can I underclock the FSB from 266 to 200 and overclock the multiplier from 5 to 6.5 (to get 1300MHz?) I seem to remember reading that the early Athlons have a locked multiplier, but that there is a way to mod the chip to unlock it.
How stable do you think the processor will be after I do all this to it. and will I have to play around with the core voltage to get it to run at the new multiplier? Or should I just bite the bullet, stick the 1500+ in a drawer somewhere, and buy the RIGHT 1500+
Thank
LoTek X