It won't be "authentic/stock" but given how much room there is under the hood I was planning on making one out of fiberglass. Simple boxes are pretty easy to do. If anybody is interested maybe I'll post a Youtube video on it. But I probably won't make it exactly the same size as the original. I would prefer something narrow (so the weight of the tools and windshield washer tank aren't cantilevered so far out) and longer (I like to keep a small crowbar in my tool kit, plus some spare parts).
Thanks for posting this link because there are a ton of photos. I've never seen so many good views of this unit. It'll be a great help making something to mimic it.
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1981 F-250 Custom. 6.6L V8, 4 barrel Holley carb, ARA aftermarket A/C.