Okay new to this so bear with me. So I was replacing my oil pan gasket and my rear main seal I look up into the block should be number one cylinder and I see all these dings on the Block itself. I check piston rod ran my hand all in there and I didn't feel anything what could these things be?Or what are they from I also when starting up a straight-6 it's got a little Clank to it when it warms up it goes away and the noise is in same spot. Lmk what y'all think. Thanks