I'm assuming the sticker shock has you all shook up, and you're meaning "your 430" tractor, instead of 440.
With that out of the way, the part number for that cover is G1328. There is a place on ebay that has new ones for like $69.00. Note, that is just the bare cover plate, but may be worth it if yours needs completely rebuilt.
I went oto Messicks, a sponsor to this site, and checked prices on the forks. First one I came to was $413.00, so went no further. However, I used Google, and put "Case G1328 cover assembly" without quotes in the search box. I found a used one, here again, just the bare cover for $125.00. But like 1600 hits, and naturally not all had to do with a Case tractor, but many were.
The good news is, that cover assy. is/was used on many models, so chances are there are some decent used ones out there. There are a couple options, and a lot depend on how soon you want it going again, vs. 3 grand for a total rebuild. You can save a search on epay, and hope something comes up soon. You can call salvage yards you find doing a Google, or similar search engine search, OR.., place a "want to buy" ad on TractorHouse.
http://www.tractorhouse.com/Default.aspx I've had pretty good luck finding hard to find parts using this last option.
You will need to register, and give some contact info. You could list is as needing the complete cover assy. I'd guess most salvage yards will, or should give some sort of warranty, or if not happy, you can return.
I have had yards contact me within as little as a few hours, through 36-48 hours. They quote you a price, so don't always jump on the first one that calls. I have even had them lower the price, because I got a lower price from another yard. Just be honest with them, and have them check if they don't believe you... A respectable salvage yard should be honest with you as far as the condition. And if you specify it "not" to be all welded up, etc., then you have somewhat of a leg to stand on, if it is not.
If that is the way you choose to go, I would definitely ask them if you are not satisfied with the part(s), can you return them, and remind them, "at their cost".
I'm guessing the smaller yards that may have these models, the tractors are still somewhat intact, so they may not know the exact condition, until they remove it. The larger yards disassemble, and inspect parts anymore.
Hope this helps some....