2008 HHR 2.2 engine near Il or In
 

Anything interchangeable.

Welcome to the site, a 2007, 2008 HHR, Pontiac G5 , Cobalt, Saturn Ion.
the 2006 is different and the 2009 is different.
LKQ has cross referencing to confirm a used engine fits.
first off why the engine swap?
did the timing chain break?

https://www.ebay.com/b/Complete-Engi...615/bn_1350282

Rod knocking.
 

Knock at first start then smoothes out quick.

Assuming a rod or main.

How many miles?
Did you drop the oil pan and check the rod bearings?
A start up knock could be broken front timing chain guide ,
broken timing chain tensioner.
are you able to listen to the engine with a mechanics scope, (screw driver) whilst your assistant starts the car for you . It it knocking high or low, drivers or passengers side?
It could be the oil pump rattling on cold start.
It could be upper engine mount worn out.
iIt could be the serpentine belt and tensioner, binding.

Sixty days rule, thread closed.