I Quoth:
Symptoms
Its very noticeable when first starting it up, seems to go away once it gets warmed up.
End Quothing.
My stock answer for anything that sounds like a lifter, but isn't a lifter is to tighten the exhaust manifold boltsEspecially when it warms up, the sound starts going away, or lessens.
Probably not even a bad gasket. Just loose bolts.