Difference 2500 or 2500HD

I recently purchased an 04 GMC 2500 (non HD). I have been thinking about putting a leveling kit or a lift kit on it but everything i look at is for 2500HD. Can anyone tell me what the differences are between the two, and what would fit the plain 2500. thank you

The main diffrence is your axles. The 2500 would be 6 lug and the 2500hd would have 8 lug. IN some cases your rear end would have a diffrent gear ratio