I have put new hood springs on my 47. The way I have done it is lower the hood as far as you can but still get to the springs and install flat washers in the gaps, I used 1/2 inch washers. When you have as many washers in as you can get then open the hood as far as possible, then you should be able to pry the spring off the hinge. To install new springs I used a floor jack that I welded a  tab with hole to the axle so you can stretch the spring and install the washers. Once you get the springs back on the hinges you just shut the hood and pickup the washers. 
I have used this method a number of times, just remember to use caution.

Back in the day when I was a body man we just muscled them into place using a large slot head screwdriver as a pry bar. Here's an idea I found using Google: https://www.youtube.com/watch?v=bpspWtE26Iw&t=109s