1993 Toyota 4x4 Pickup! Engine Knock?

My question is, I have a knock in the engine that sounds like it's up near the top of motor or intake manifold. It isn't a ticking sound like a lifter, rocker arm or exhaust manifold leak. It's more of a hard knock, at idle it's not as noticeable but as engine revs it gets very loud. I will be doing some investigating this weekend but was hoping someone may have had this issue & could share a general direction to consider. The engine does have 250,000+ miles but still runs strong. It's a V6 3.0 motor! Thank You!

ElkNut1