[Chipper Chapman]

The bellhousing is missing the highest bolt hole on the right side, the one your dipstick tube usually anchors to, not a big deal just that you have 5 bolts instead of 6.

The mounts are different but all you need to do is make a peice of plate that adapts your gen 1 mounts, There is 1 bolt hole that is in the correct location for the lower bolt of the gen1 mount, I think its the front lower hole.

Must use LS style flexplate, AND if you're lucky you're 6.0 is from an earlier truck, 99-02 i believe, because they have an adapter bolted on with the flexplate that accepts a normal gen1 torque converter pilot. If you don't have one of these you need a LS style converter.
(gm did this because of the overlap of 2 gens of trucks and engines which both used the same 4L80E trans/converter)

You may need to elongate the converter bolts holes in the flexplate for use with normal converters, some had a metric bolt pattern that is close to the older large pattern but not close enough.

Hope this helps