What size frame is it? Nema 17 or Nema 23 are the most common.
How many wires does it have coming out of it?
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www.reprap.org] has all the specs you need to see if it'll work.
Generally, if it's nema 17, has 4,6 or 8 wires, and has at least 19.4 oz/in of holding torque, you'll be fine. At least one motor with less torque than that has been used successfully, so even that is fine.
The amp rating of your motor is a little high (2.5A? That's a hefty little motor, isn't it?) the pololus are rated for only 2A, and that's with some serious heatsinking. It shouldn't be a problem though - the recommended specs already take into account that you can't run the motors at their full rated current anyway, as they're usually rated to run at 100C, which would melt all our nice plastic brackets.
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I'm building it with
Baling Wire