This helped but I also had to increase the permgen. Changed it from 64 to 128, might be too much or not but the pack loads fine now.Here's how to install the manual version with multimc:
1) Download the pack
2) Open MultiMC and create a new instance minecraft version 1.7.10
3) Launch the instance to check it runs
4) Close the instance, press edit instance and install minecraft forge version 10.13.3.1401 or higher
5) Launch the instance again to check it works
6) Open the instance folder and drag the "minecraft" folder from the pack into the instance folder. Select overwrite when prompted.
7)Launch instance and it should all work.
If not post here or on the Github and I will see how I can help