I found this ....I might have a few leftover chunks in the garage. Mine now is a hybrid/bastard of a 100 upper, and 80 lower. Give me a day or two and I should be able to give you a spline count and size.
LandCruiser IFS 100 Series Steering Shaft Extension - https://shop.snakeracing.com.au/landcruiser-ifs-100-series-steering-shaft-extension/
Steering shaft extension ... will solve the problem and work just fine. For anyone else looking, it's a bit spendy but there is nothing in the US that I could find.