Some comments as the former importer/distributor for Kaymar 4WD for a number of years as Long Range America (LRA) and we also sold fuel tanks from Australia.
Kaymar was a family owned firm for several decades. During our time, the firm was sold to a corporate owner that then sold to another corporate owner, etc. We ended the business relationship and Kaymar is now offered by the same folks that own Mule Expedition in Seattle area.
I have since retired and no longer have a financial interest, but my former partners have grown LRA with front and rear bumper options for many different makes/models from The Cruiser Company in Australia. Suggest you check out some other optiions such as that mentioned above, and from Long Range America as here:
76 Series Toyota Land Cruiser - Rear Steel Tow Bar with Side Panel Hoops | Long Range America - https://longrangeamerica.com/product/76-series-toyota-land-cruiser-rear-tow-bar-side-panel-hoops-the-cruiser-company (photo below). Apparently a special order, but they ship from Idaho, not Australia.
The back of your 78 Series is very similar to that of the current 76 Series. Cannot speak to whether the Cruiser Company kit will fit, but we had a number of similar Kaymar bumpers fitted to light duty and heavy duty 77/78 Series Land Cruisers with minor modifications. I had a Kaymar on my LJ77.
Good luck.
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