Looking for advice on a '71 Demon

So I've been looking for an A Body for several months now, to pair with my '74 Rallye Challenger and add to my Mopar Collection.

I've come across a '71 Demon that looks to be in very good shape, most importantly the body seems to be in good shape, which will go along way towards putting fresh paint on it.

Here's the catch though, it was an original 6-cylinder car, that has been converted to a 318. The seller also has a 340 to go with the car.

My question is this, is there anything specifically I should look for/be wary of when it comes to a swap like this? My thoughts immediately go to the K-member and wondering if that should have been swapped out going from a 6 cylinder to an 8.

Now admittedly, going to a small block makes me think the original might be sufficient, but I wondered what others thought.
Not to mention, again, if there are other things I should be aware of when/if I go to look at it.

Thanks!!