402 chevy big block rattle?

[Erik'sGrandAm]

I was thinking about getting a engine from abuddy its a 402 .30 over . Problem is that the engine has a strange sound to it , sound like middle of block , like i said rattle not a knock or a tick rist pin? He clams he pulled cam and found rounded off lobs and replaced cam but same sound. Any Thoughts would be great. I like to fix this engine or rebuild it .

 

[wreckrunner]

check flexplate probley cracked convertor bolts loose we just had a big block same way the noise sounded like in middle of engine it was flexplate had 3 cracks in it