idk if i can get a clear picture with the heads on the car. but i think your rite, may have the inserts already so ill try the 7/16 bolt.

the thermactor tubing is all removed. but i still have the hose running from smog pump into a valve and then pipe runs into h-pipe. do i still need that, or can i remove that?

 

Hose running from h-pipe feeds exhaust gas into the back of the heads. It puts inert gas into the cylinders to lower combustion chamber temperatures to improve emissions by reducing NOx levels. Plugging those ports means you just have an exhaust leak if you don't plug the tube coming from your exhaust. I welded the X-pipe closed on my stang when I removed the emissions ****.

 

If the 7/16" bolt fits in there, then you already have inserts. The thermactor plug inserts SHOULD seal the hole. If you feel that you are actually getting a leak from back there then you probably need to remove the inserts and seal them. If you had emissions equipment on the heads, the holes may be carbon caked.

 

ok thanks. ya i thnk i must have the inserts already. bcuz it seems like 7/16 is the fit.

also the thermactor stuff is removed. but that pipe leading into the h-pipe and running into the smog pump is there. will this cause anything? or sould i remove that pipe as well?

 

remove all that **** and cap the midpipe.

 

yeah dump it...if the smog pump is bypassed it'll make noise, and its just dead weight anyways

heres the thermactor plugs you'd need or already have it sounds like