What a great family project, and with long term curation in mind, I like it!
You probably know this already, but that particular body style (1961 Belair Sport Coupe) is very low production, and having a 348 in it is even more rare. There were nine thousand some made (I can look that up) and even fewer had V8s. We don't have any way of knowing just how many had 348s (the other V8 was the 283), but I would venture to guess very few.
Keep us posted as you move along, we can help with advise and encouragement
.
Cheers!
TomK