What's the stock wheel size from the 2004 skid?? I think Polaris went to a slightly bigger wheel in the rear that year. The axle may have been made for previous sized wheels.
Regardless it shouldn't be that far off. But it makes a difference.
If you have the offset UP and FORWARD and the wheels are too high so that they don't touch the track, then you also may have possibly gotten an axle for the 9" wheels.
Now if you have the kit installed and all seems right, except that your track clips are rubbing the bottom back corner of your rail ends, and the track is tensioned to where you want it, then your gonna have to either grind the bottom back corner for clearance, or knock a little bit of the block that is part of the axle kit that slides inside the track tensioner rail windows. I've done this before.
Here's a little secret about that product and other products made by that company. NOT ONE SINGLE THING THEY MADE WAS PREVIOUSLY TESTED.
Just a buncha ideas on stuff to make that looked cool cause it was CNC'd, and made in the middle of the summer then sold. The first axle kits made, that center section was a hollow tube that screwed into the two inside blocks, that tube basically failed and a guys entire axle split in half, not pretty spearing a track on the rear end. First Hyper-Lite clutches made had aluminum towers that snapped off. Replaced by steel ones that made the clutch the same weight as the clutch it completely copied, a Cat roller.
BTW, if you got 136" extensions, your real problems lies in the fact that with a 8" wheel, your sucking up all your track with a bigger radius, that's why the wheels are forward from stock, but then you get your problem, track clips rubbing in the rear..... Might wanna consider stock.
Kinda hypocritical of me, seein' as I run a 9" offset wheel kit. But that's a 136" skid, set back, w/ 144" track.