The Gen V LT1/LV3 engine mounts are different but you can buy adapter plates. But they are LS to LT. So you would need to make SBC to LT adapter plates. Easy to do its just flat piece of metal.
The bell house is different namely the top bolt hole is off set which shouldn't matter as you just leave it deleted but the LV3 lacks a bolt hole at the upper pass side so you only have 5 bolt holes in it. But you would still need a crank bushing for the transmission I believe. But you can get 4l60e or manual bellhouse from GMPP.
Note the bell face difference.
Also the new motors lack powersteering pumps. You can get mount brackets for them though. Well at least for the LT's you can.
Also it will have a vacuum pump on it to help with brake booster as it certain ranges it lacks engine vacuum.
There are places that can rework harness and tune the ECM as well. Speartech is one.