Mike,
Depends on which new drums you are talking about. Boling Bros make excellent US-made drums that are designed to SLIP on stock or replacement stock-style hubs. Only change is you need to remove the stock studs and install slightly oversized knurled studs. They sell all the parts you need.
If going this route, then yes you can reuse your stock '40 hubs.
Member Krylon32 AKA Gary @ Cornhuskers in offering members 10% Boling Bros brake parts.