Here's my trick:

towards the back of the block, like under the #4 exhaust port, is a clamp that holds the hard coolant line to the block. Loosen/remove the clamp. It makes it much easier to manipulate the line for a correct fit.

Also, put the little seal in the pump and shove the line into it. Don't put the seal on the line and then press it in. A wee bit of lubricant on the seal will help ease things together.