Thanks, Mike, and everyone who responded. Through the efforts of chp1982 I was able to get one. A used one, but it works, and should do the job. I am going into the shop tomorrow morning at 8 am to bring it in. With what it took to find it I almost feel like bringing in a trumpet or bugle to announce to the shop (and the city) the arrival of the coveted Exhaust Gas Riser valve, which had stopped the project dead in the water.
I sincerely appreciate the advice, assistance, and help I have been fortunate to receive from members of this forum. The restoration of 0327 (and virtual reincarnation of 0255) would not be happening without it.
I had, through the internet, looked all over the country and the world to try to find a nos part. I had said that these things are about as hard to find as a genuinely honest politician in D.C. So my faith in politicians is restored!!!...just kidding...I wouldn't go quite that far...