[gubmentcheze]

I bought a GT Pantera off Craigslist a little while back. Since I've been on these forums, it was pointed out to me that the forks are toast. My buddy gave me a second bike a GT aggressor. Not nearly as nice of a bike, but the forks are ok. I have yet to hit a trail, so I don't even know if I want to commit a heap of cash to a bike. I want to swap the forks and need to know if it will work? I'm replacing a Rock shox quadra 21r with a rock shox judy xc I believe. I have pics I appreciate any and all help thank you very much. I can supply more pics if necessary for a better assessment. BTW, my LBS wants $200 for a used fork and I only paid $60 for the bike.

 

[reptilezs]

umm measure the steer tubes. you will also need to swap crown races. look up fork installation at the park tool site

 

[trailville]

I have a '94 Pantera that I put a '96 63mm Judy XC on and it works fine. It changes the geo a little, but not huge. I can't tell for sure from your photo if your Judy is 63mm or 80mm (though I'm leaning towards 63).
At a quick glance, it looks like you probably are ok on steerer length.
The 2nd photo almost looks like you have a smaller diameter steerer on the GT, but I'm thinking that may just be a bit of an optical illusion based on the different types and colors of the stems. Easy enough for you to measure though.
As reptilezs mentioned, you'll have to swap the crown race, but overall it's not a lot of work to swap a fork. Also gives you an opportunity to clean and grease your headset bearings while your at it.