Forget about EXIF.
300x1.7=510mm that is 510mm no matter what camera it is on.
On 1.5x crop camera your magnification is still 510mm but your FOV is 765mm.

Now, it all depends which cameras you compare.
D7000 and D800 are exactly the same for example. So no extra pixel reach. Just like taking the picture FF and cropping yourself.
D7000 to D4 you get a lot more pixel reach with D7000.

All above is technically speaking. There are other factors involve.