My piping model starts with node 10 and extends through node 520. I know the exact location of node 380. Is it possible to specify the coordinates for node 380 or is the beginning node 10 the only one that I can specify the coordinates of? Thanks.

You can only specify the first node in the model. However, you can use the "distance" toolbar button to find the distance from 10 to 380, then specify the coordinates of node 10 using that amount so 380 is where you want it.