I just finished doing my timing chain and lifters and my truck is pretty quite now however i can still hear a faint noise. The truck has 280,000 miles on it.

I purchased the oil pan gasket when i did the timing chain, thinking i would need to remove to replace oil pump however that was not necessary.

I still plan on removing the oil pan gasket shortly to remove any old broken timing gear plastic parts etc. I was wondering if it is possible to replace the rod bearings if their is play while still in this engine?

I am also going to replace the manifold gaskets as I see a head missing hear and their in the rear of the manifolds.

Any other possibilities that might help without removing the block?