69 Cutlass motor swap

[HawkX66]

I know it's pretty straight forward, but are there any issues that I should be looking for when swapping a 70 454 into a 69 Cutlass? I'm about to pull a NOM 350 Olds out of a friends 69 and put in a 454.
I'm planning on finding something with an overdrive to replace the TH350 that I'm assuming is in it. Any flavor better than the next for that? 4L60? I'd like something with the most straight forward, non-invasive install. The body is nice. He's a car enthusiast, but knows nothing about mechanics so I want to keep it turn key for him after I'm done. He wants a nice reliable cruiser with plenty of power, but no more than a stockish 454.