this is long but please bear with me. Recently the 355,000mile brick failed the MD emissions inspection (barely). the entire emissions control system has been throughly serviced with the exception of the cateletic converter. I had been running my timing at approximatley 9 degrees btdc to compensate for some serious head work that I did 2 summers ago (.017 mill job) which as you may know is way past volvo max spec. The car ran fine but I was concerned about what I thought was detonation. As it turned out the bottom of my fan shroud was broken and causing it to contact the fan on acceleration (who would have thought that???). I discovered this after replacing the knock sensor. I drove the car approximately 30,000 miles at 9 degrees BTDC untill i recently failed the emissions inspection on the hydrocarbons reading. I pulled a spark plug for a visual impection (first time since head job) and the electrode was not bad looking, but did have a slight bit of blackness to it. I then advanced the timeing to factory spec 12 degrees BTDC and ran the car pretty hard listening carefully for knocks....no knocks and great performance...the idle even smoothed out a bit. when I got out of the car I inspected the tailpipe which was slightly black from the previous 30k miles ov driving so I cleaned it off only to discover that it was really rather hot...that is too hot to touch...is this normal? I am going out to pull a plug after cool down to see what it looks like after the timing adjustment. please advise as to tail pipe temp.