How much to replace the engine in my 2008 chevy silverado 1500 ltz 5.3

What is your question?

There is a knocking sound and it barley moves,runs extremely rough .i took it to a shop and they said i needed the top end rebuilt or a new engine and quoted me a price of $9,000.

What makes this problem better or worse?

It does it all the time

How long has your 2008 Chevrolet Silverado 1500 had this problem?

About 5 days