These Bilsteins should cover up to 4" of lift. These are for my 1970.
BIL33-185606 Front
Collapsed Length (IN) - 14.13
Extended Length (IN) - 22.58
BIL33-185552 Rear
Collapsed Length (IN) - 15.91
Extended Length (IN) - 25.93
I didn't install it but probably something like this: Stock Air Filter Adapter - Weber - FJ40, FJ45, FJ55 1969-1974 - https://cruisercorps.com/products/stock-air-filter-adapter-weber
I'll be pulling the manifolds first to have them resurfaced, while doing so the Weber will get a full rebuild as...
Yes... read this: 1970 FJ40 restoration - https://forum.ih8mud.com/threads/1970-fj40-restoration.387351/
And some high res shots on BaT: https://bringatrailer.com/listing/1970-toyota-land-cruiser-fj40-32/
I spent many years in the engine machine shop business so my comments are from that point of view.
IF the engine seized from lack of oil, which, by your description it did, I would most definitely want to pull and tear down the engine. An engine seizes because two surfaces come in contact with...