4L60E & 2004 LQ4, nuts and bolts ??

[solidaxel]

The question I have is I just picked up a 5.3 and 4L60E and they were not mated together, but from the same yard. I need to add some bolts (8) to put them together!

What size MM bolts do I need, as I am just learning MM , I am from the "old" school of inches !!

Also the transmission has 9 bolt holes for mounting and the engine has the top bolt hole plugged, I don't think this will be a problem "but" just asking, 8 bolts should keep it in position !!
The bolts that go into the oil pan, are they different than the engine bolts, or all the same length and pitch?

The other question I discovered on the foot feed (gas peddle) there is another plug or vacuum switch, what is this for, do I need to worry about it?

The transmission looks like it has a new T. converter as it is freshly painted, or very new looking, how can I tell what I have, should I replace the front seal while it is on the floor?

The cast iron block has a 4.8 and a 5.3 casting on the rear of the block under the flex plate on the passenger side below the cylinder head, and the yard "assured" me that the numbers said it was a 5.3. It came from a 04 Tahoe, at least that is the one he showed me and by the broken bracket I think it is the same engine.

Thanks for your help