Can thermactor passages be drilled...

Discussion in 'Fox 5.0 Mustang Tech' started by Bigstang1, Dec 18, 2003.

  1. Can thermactor air pump passages in gt40p heads be drilled and tapped by an ordinary machine shop? Or does it have to be an automotive machinse shop? I have a friend with a machine shop and was just wondering before i ask him thanks
  2. I would think any machine shop that is good could do it.
  3. Yeah, don't worry about it, i don't have any problems without EGR :shrug: I still pass emissions
  4. hey, I just got GT40P heads- can someone tell me what the rear of the heads should look like if they are emissoins legal?

    my heads have the cap in the rears on both--
  5. P's do not have EGR if they are P's then you can't tell....

    If they are GT40s, then you should have a hole in the back of the head, and a hole at the end of the insides of the exhuast ports....which is what this thread is about
  6. no actually this head is about GT40P heads isnt it?
  7. yes, I was referring to the thermactor holes in the exhuast ports, which is what Bigstang1 is asking if he can drill his own
  8. I have P heads with thermactor holes - but they were drilled in there and tapped.
  9. Arite i will ask him soon if he can drill them but i will need to know where to drill to. There is just one tapped hole in the back of the head that goes to the rear exaust port only? if somone could explain that would be excellent. thanks
  10. the hole goes all the way through the head - that is the channel that the bumps in the ehaust port feeds in each exhaust runner. A good machinist will know what to do.
  11. Alright I think some people are getting confused. He is asking about the exhaust gas passage for the Smog pump system. (themactor system) Any decent machine shop should be able to drill the themactor passage since GT-40P's do not come with the thermactor hole drilled (if the casting itself allows this). The EGR system is different then the Themactor system though both deal with exhuast gas and emission controls. The EGR passges are present in most GT-40P heads (I believe later castings do not have it), if you look in the number 2 and 6 exhaust ports you can see the egr passages which go through the head and into the intake. Both the EGR passages and Thermactor holes can be drilled if the castings allow which I'm sure they will.

    I have a question regaurding the EGR passages, what is the best way to fill them? Since I plan on deletling the EGR system and using non-egr intakes I figure fill the passages in the head to, do they hurt flow much? Thanks.