What's needed to make this work?
 

I have a 5.3 out of a 2006 silverado pickup. It did not come with a trans. There are a couple of 4l60e for sale around here from late 90's camaro z28s. What is needed to make this trans work with this year engine?

A '98 or '99 should bolt right up. I only say those two years because you said you have access to late 90's 4L60E's.
Later years will work too.

My options are

1997 z28 - 80kms on it
1995 z28 - 140kms
1999 z28 - kms unknown

The 99 is the only one in the list that will bolt up easy.

^^^ he is correct the only one that will bolt up without modification is the 99.

what would need to be done to make the 97 bolt up?