[BR3W CITY]

Your swap shouldn't be any different than the other 60-62 guys, and it will still have plenty of shared components with the 63-66 swaps, which there are many of. You might be able to get more ideas, faster, by taking a look at what the other 60-62's have put together. The "what ya got" thread up top is also helpful for general ideas, and to point you in the direction of members with similar swaps.

IS the 61 stock right now? Drum brakes, X-frame(iirc) etc
So many of these trucks have had 30+ years of changes, so its not uncommon to find modified frames, swapped crossmembers and brakes (especially this!) and other changes.

Motor mount suggestions will be based partially on this^. Its kinda like throwing darts at a parts list until we know exactly what your working with (and what you want to do with it). Just on mounts for example, people have used everything from swap adapter plates, homemade mounts, aftermarket perches/stands, and entire custom xmembers. In many cases, all of the above can be made to work.

So, there I made things 20x more complicated.