Immersive Engineering .84
Gaspunk 1.4.5
Forge .2732

Crash: https://pastebin.com/8u3BR4Qi

Upon loading the game, it crashes around the post-initiation stage, dealing with ItemStacks. Uninstalling either Gaspunk or Immersive Engineering fixes the crash

Looks like it is mostly on the side of Immersive Engineering, but I will investigate further.

I've asked Blu about this as well, and he mentioned Gaspunk may be shipping an outdated version of the IE api

Not the cause, but it is fixed in Gaspunk 1.4.6 anyway (pending curse approval)