are 3 into 1 extractors made normally like that with a mass of welds at one end??
There are 3 ways to make them-
1. like in the pic,
2. like in the pic but pipe joint twisted 90° (Perry)
3. with the 1-4 pipe join a few inches above where the 2&3 pipe does (Maniflow).
They all work, GR says with a big pipe on the bottom they will handle up to 120HP.