Kenneth - I believe the sensor in the first picture controls the EGR, most people remove it. I'm not sure about the other two.
Rat72 - Where do you get LT1Edit at? How much?
I used a Howell Engineering harness in my 48 and had no problems.
Here are a couple of links that might help:
http://www.fierolt1.com/top-end.htm
http://www.fierolt1.com/bottom-end.htm
http://www.theherd.com/articles/lt1_cool.htm