gt-40p and thermactor drilling...How?
 

If my gt-40ps aren´t drilled for the thermactor air passage, can I drill them in the same place as the stock heads? How far can I go?
Or I can leave it this way and disconnect the smog pump? No need for emissions on my location, by the way.
I would appreciate any comments.

I have been wondering this same thing. I figure it should be a simple drill and tap into the same location in the head as the stock mustang heads but would love to hear someone with personal knowledge verify this before I make swiss cheese of my heads. I know Central Coast makes this modification but havent heard any of the details. Hope you get a response!

If you don't have emissions in your area, then don't worry about it. Just ditch the smog pump and cross-over. Cap/plug the air tube to the H-pipe and awayyyyy you go.

Here's another vote wanting to know how this is done since I'm in California, home of the smog police.

To pass the smog police here in the NE Ohio area, I bolted the air pump and cross-over on for the test. The thermactor holes have never been drilled on my heads so the pump was basically dead-headed during the test. I didn't even haven the air tube connected at the H-pipe, it was just hanging there free. The car still passed the dyno test with flying colors. At the time, I was running a 224/232 cam with 110 CL and 30# injectors.

Simple as that? The car will run and idle just fine?
But, if I had to drill, is anything I should be aware, or I can go deeper into the head?
Thanks for the info, I really appreciate that.

The hole in the head for thermactors is actually connected to the valve cover bolts, stick a pick into the hole see how deep it is, and use this to determine how far you need to drill. Also if no holes for thermactors are there then why would the hole or tube as some would call it be there

The P's aren't drilled from the factory. The EGR passage is probably a remnant of the original design and casting molds, but since the later model Explorers didn't use the thermactor passage, Ford simply cut one of the last production processes which was drilling of the crossover passage as a means of reducing cost. The Explorers took the injected the air directly into the exhaust manifold instead of through this thermactor passage.

Personally, I wouldn't drill it even if I lived in CA. If the smog police want to see the cross-over in place, then just simply bolt it to the back of the heads.

Thanks again, I´ll probably let it alone. All I gotta do is a little polish and porting work (cut the exhaust thermactor bumps, etc.)
Lol, as you see I´ve been studying...