HP exhaust manifold question......strange fitting??

[69 OUR/TEA]

     Hey all,I have a question on my 69 HP manifold that has a fitting screwed into the top,like for some kind of EGT gauge.Don't know if this original or not,never seen this before nor heard of it.Maybe some of you could shed some light on this.It unscrewed no problem,here are a couple pics.......

[tatrick2me]

Every CA car I've ever saw had this. Even in 68 they had to install air pumps on there cars for emissions.

[y3chargerrt]

My 69 is an original Ca car. I believe that the manifolds are original and have no such fitting.

[ITSA426]

Don't know for sure but that would be a good spot for a heated choke tube on the rear carb of a dual quad set up.  It seems like the manifold pickup used on earlier set ups.  An idea! Thanks.  It doesn't look original to the manifold, and I've seen that fitting used in other places.  I just can't remember where right this second.

[john108]

I purchased my '68 Charger R/T, off the showroom floor, in 1968 in Southern California.  No Fitting and no air pump.

[ITSA426]

Fine threads cut into cast iron is generally not a good idea, and the drilled head bolt looks to be from the aviation world. 

[John_Kunkel]

Definitely not factory, the bolt is an AN7x series aircraft bolt cross drilled for safety wire.

[375instroke]

I'm from California and have never seen that or a smog pump on a pre-mid-'70s Mopar.

[FLG]

Yep sure looks like an aircraft bolt. Ive seen 1 car with such a bolt (though no hole in the middle) and that was a 67 T-Bird. Those aircraft bolts were used to hold the calipers on, still got em laying around somewhere. Dont know if it was "supposed" to be like that but there were 2 on each side so who knows.