Inspired by this thread.

It's fairly common for people doing turbo conversion to want to eliminate the T-VIS system on early 4AGs.

As the manifold bolts directly to the head if you remove the T-VIS plate, it would seem logical to simply bolt it up. Unfortunately, this has potential problems:

As you can see, the 'valley' between the individual pipes comes perilously close to the port. In a forced induction engine, it would be almost impossible to make it seal.

On the other hand, with the T-VIS plate in:

You get heaps of gasket area and all is good.

So, to remove the T-VIS, I'd suggest you do one of the following:

- Weld up the valleys on the manifold and grind the face back
- Gut the T-VIS plate, and fill the shaft holes with epoxy or weld
- Purchase a T-VIS eliminator plate - I've seen them around, Google is your friend
- Simply remove the butterflies from the existing setup and leave the shaft in there.