CV axle interchangability???

[Petersubaru]

I have gone to 3 auto parts stores, when giving them the model year of my cars ,2 stores said none of my CV axles can be interchanged...the other store said maybe...I have an 86 loyale,4wd,carb, manual and a 86 turbo,2wd,auto and a 90 4wd manual,single range...on 2 of the cars,the inside spline count ids the same..thanks for any advice