Some added info from what I said above,,,
My NH service manual for my 715B snowblower includes a section for the 702C front blade. My manual is a late 90's version and covers these attachments for the 20 series compact tractors (1320, 1520, etc). The TC30 would be the same as a 1520 as far as my manual is concerned. In looking at my manual, it appears that the rear frame (what I called the undermount section above) section that you have is different (similar but different) from what is used on the 1520 in that time period. The position of the front mounting brackets looks slightly different, maybe a little further our front, and the rear mounting is different. The 1520 shows the rear attaching to the side where the main loader brackets attach.
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Looks like you might have some modifications to make to the rear frame to make it fit. Just an additional thought, if you have a loader and or a belly mower, in order to avoid having to remove the heavy brackets that are attached to middle of the tractor, I would extend the undermount frame to the rear of the tractor and attach it in the same way as my front snowblower is attached in the rear. The blower has bracket that is attached underneath the rear hitch drawbar. The undermount frame attaches to that bracket with one pin
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