I can't help with the fitting of power steering but I switch between modern cars and Land Rovers without power steering without too many problems. For years in the UK I also drove cars without power steering.
There are potentially a lot of things that can make the steering heavier than it should be eg. incorrect tyre pressures, steering joints worn/dry, steering relay full of rust, swivel hubs worn or wrong pre-load, steering box too tight or worn etc. etc.
Assuming everything is AOK then the single most important thing with unassisted steering is only turn the steering wheel while the vehicle is moving.
If you get yourself into a situation where you need to turn the wheel while the vehicle is stationary it's very hard.
Even a 3-point turn can be handled easily if you plan ahead and at the last minute turn the steering wheel so the wheels are in the correct position for the next part of the manouvre.
Easy for me to say, but all it takes is some practice. Remember that years ago power steering wasn't common and we all managed OK.
Best of luck,
Colin
'56 Series 1 with homemade welder
'65 Series IIa Dormobile
'70 SIIa GS
'76 SIII 88" (Isuzu C240)
'81 SIII FFR
'95 Defender Tanami
Motorcycles :-
Vincent Rapide, Panther M100, Norton BIG4, Electra & Navigator, Matchless G80C, Suzuki SV650
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