Doing the seals might as well change the springs. Changing the springs might as well put a cam in it. 
Just a thought,,,If the smoke is black and a wee bit rough idle at start,,,The first thing I would do is,,after it set a little while,,pull the vacuum hose off the fuel pressure regulator, engine not running of course,, and see if any liquid fuel drips. if it does replace the regulator,,,This is very conman in all vor-tech 5.3 ,, 6.0 and 4.8 gm gasoline engines...Hope this helps...Thanks jay
This is correct. Been there done that.
At 170k, if you're planning on keeping the truck, i'd not worry about the valve guide seals and just start looking into replacing or rebuilding the motor. it's going to have to be done sometime soon anyway...... if you're not going to keep it....it's time to say goodbye. : )
Umm newer GM motors will last well past 200K without a problem.
Does it crank a little bit before it starts? If it is the fuel pressure regulator, it will usually have extended cranking time.
Blue smoke = oil
Black smoke = too rich a mixture
White smoke = condensate in exhaust or anti freeze getting into a cylinder
Rainbow smoke = really good drugs
If it's oil, it'll be blue. If you are not using much, the thing to do is to rule out cheap problems as suggested above, and to drive it and enjoy it. With 175 k of well maintained miles, I suspect you can get another 50 k with not too many problems. Valve seals on GM used to be a big problem. I have replaced a bunch with Ford "umbrella" seals. However, it's my understanding that they fixed that design problem before your truck was built.
You might pull the plugs and see if they all look alike. the problem, if there is one, may be associated with only one cylinder. Could even be an oil control ring sticking a little on start-up. Given regular oil changes, probably not.
Black smoke = too rich a mixture
White smoke = condensate in exhaust or anti freeze getting into a cylinder
Rainbow smoke = really good drugs
If it's oil, it'll be blue. If you are not using much, the thing to do is to rule out cheap problems as suggested above, and to drive it and enjoy it. With 175 k of well maintained miles, I suspect you can get another 50 k with not too many problems. Valve seals on GM used to be a big problem. I have replaced a bunch with Ford "umbrella" seals. However, it's my understanding that they fixed that design problem before your truck was built.
You might pull the plugs and see if they all look alike. the problem, if there is one, may be associated with only one cylinder. Could even be an oil control ring sticking a little on start-up. Given regular oil changes, probably not.
should of got a dodge
An engine builder/automotive machinist told me once he prefered to run without valve seals. That it provided a little extra lubrication on startup, more so after sitting long periods of time. He felt his engines lasted a bit longer (lots of older 327s 350s and 454s) but used a little extra oil, not a problem if you check it regularly. BUT most of his customers did not like that as would smoke a bit on startup so mostly this idea was just implemented on his personal engines.
Well, I have a great mechanic who has offered to check it out and replace seals if needed. I will pass along all this great info. Thank you guys very much. I would like to keep it a while longer as my 15 y/o old son would like it in a year.
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