Question I have is... when you did the swap, was it swapped complete? Or did you have valve covers off? Intake manifold off? If you had it disassembled and were working on it did you come short on a bolt when you were re installing?if you installed in complete and just dropped it in then I'd imagine your chances of something being in it would be low. I'd also imagine that if you dropped a bolt or something small in the engine it would be very loud. Not just a noticeable noise. It's a used engine? Was it ran before pulled and reinstalled in your truck? Did it make any noise when you tested it? If it wasn't tested prior then the engine could have had this noise prior to you working on it.

 

yes it was a complete swap and I did remove the manifold, I actually removed a lot. And I drove the truck that I got the engine from and it was fine. I believe it's because the pressure from the engine. Since it took me so long to swap it I guess all the pressure released and made the valve loosen. Correct me if I'm wrong but that's what I was told