Guys, thanks for the replies. Here is a little history on the truck and some answers to your questions.
I bought the truck new with 28 miles on it. I ran conventional Mobil untill about 14,000 miles and at this time I switched to Mobil 1 which I run to date. I always used the 5W-30 weight and always changed at 3,000 miles except for one 5,000 interval last year. Truck currently has about 42,400 miles on it.
I first noticed the cold start tapping noise last year at about 32,000 miles. It doesn't seem to do it every time I cold start it, but it does seem like it is getting slightly worse. The tapping usually quites down within a minute of running.
I had the intake manifold gaskets replaced at aroung 24,000 miles because of coolant leaks but this is the only time this engine has been opened up.
The tapping sounds like its coming from the lifters to me, like its taking awhile for them to pump up. The 5W-30 supersyn supposedly flows down to -54*F and the 10W-30 supersyn down to -49*F. I don't know if this small difference in flow would cause the louder tapping. The tapping was probably at least twice as loud as it ever has done before. The temperature at the time was about 75 degrees. I would hate to think how loud it would have been if it was really cold out.
I use an AC-Delco UPF52 filter which is the gold series filter that was out before they were discontinued. I still have a small stock of them. I've been using this filter for almost three years but I don't know if it has an anti-drainback valve in it or not. Before that, I used the regular blue AC-Delco PF52 filter.
This is the first time I used the Supersyn in this truck.
My personal thought on this, is that the 10W when cold, is not getting up to the lifters and upper valvetrain as fast as the 5W did thus causing the tapping to be louder and last longer. I did notice that once the truck was warmed up, the engine sounded quiter with the 10W-30 compared to the 5W-30. I also noticed that the engine seemed to be a little more sluggish with the 10W-30 when it warmed up. This engine never has been real quiet. When I was still using conventional Mobil, I took the truck to the dealer one time because the lifters seemed to be too loud, but they told me it was normal and since I wasn't having any performance or oil burning issues, I just let it go. Probably a mistake on my part.
So what does everyone think I should do? I'm leaning toward switching back to the 5W-30, especially with winter coming. I don't know if switching to a different brand of oil will solve anything. Thanks again.