Ok here is probably a dumb question but hell here goes.The check valve thats under the acv(little round insert piece)Do you leave that in and put the block off plate over it,or do you take it out?

 

If the block off plate fits over it then it dosen't matter, If not take it out.

 

Take it out or you will hear a rattling noise from it vibrating against the block off plate.

 

It doesn't matter really whether you leave it in or take it out. If you leave it in you should use a drill to make a small recess in the back of the plate to clear the pin in the middle, or file the pin flat. It certainly isn't going to rattle...

 

In my GSLSE the gasket was enought for the block off plate pin to clear the plate. I left it in so I would no where it was when I had to pass smog again.