Engine 95 gt regarding thermactor tube Passage

[rockyracoon]

Can anybody tell me the correct drill bit and also the correct tap size and pitch that I will need to mount the thermactor into a passage that I would like to drill only into number 4 and number 8 exhaust ports of course with intersecting holes. I'm hoping that will be enough to keep my car from throwing codes

 

[rockyracoon]

I was able to research on the internet it looks like the tap is 5/8 by 11 + a 17/32 drill bit.