Nikon 70-300mm Vr 55-300mm Vr lens distances?

I have a nikon D90, but it is the same distance between a 55-300mm Vr lens and 70-300mm Vr? I mean, if you get the same distance of 300mm in both lens, or because one is FX and the other is DX, you get different distances when you look thought the viewfinder?

300 mm is 300 mm.

The fact that one is a FX lens only tells you that it can be used on a D3 or D700 without vignetting, that's it

300mm is 300mm. It is not the lens, but the size of the sensor in the camera body that creates the crop factor.

The 70-300 is designed for fx camera so you are getting exactly 70-300 on an fx camera. For a DX camera however you are getting 105-400 because of the 1.5 crop sensor. The 55-300 is for dx so you are going to get 55-300 on your d90 and 105-450 with the 70-300.