The King of weird noises does it again....

[Gray Ghost]

My truck holds the record in our club as being the one that has the strangest noises. Today a new one cropped up and I wanted to see if any of you guys had ever heard this one.

I accelerated up to 65 on the way to the bank in Forney today when I got on the highway. After reaching 65 I let off a bit to hit cruising speed and this weird valvetrain sounding noise started clattering. It sounds almost like revving a motor up with very little oil in it. At first it was only doing this at speed and not making a sound if I either let off the gas or accelerated more. Now I am beginning to hear it a bit at part throttle acceleration. Oil has been checked [I added Lucas to it last week cause my upper rings are loose and I thought it would minimize the blow-by]. The oil level is fine and it's been say 6000 miles since the last change.

I looked for something that might be vibrating but found nothing loose under the hood. As the noise progresses, I am pretty sure it's in the valvetrain, but it doesn't do it at idle or when the pedal is to the metal.

Anyone heard of this? The motor has bever been rebuilt and has at least 149k on it. I talked to a couple of friends that say I have the strangest noises and that most of them they've never heard before....lucky me huh?