Engine noise weird

[Lt.dan96]

I guys I recently went to test drive a 2017 SHO very clean 62k miles on the odometer but it make a weird noise under acceleration like this YouTube video (slight knocking):

I like the car but can't pull the trigger until I found more info on that sound. The sound was gone once hot Thanks

 

[2016SHO]

Ask about water pump change. Timing chain and tensioners should be replaced as well because they are driving the water pump. Terrible design but worth checking into and replacing now before you jump timing as I did and had to replace my head.