Practically any fuse box would work, but if the Aspen is like my '75 Duster you'll be limited in circuits and Mopar was still using ammeters which are a major pain to switch to voltmeter. You will also have to consider bulkhead connectors and all of the other connections. If you don't have much electrical experience it might be wiser to go with an aftermarket wiring harness. In any case I'd rewire the whole car as I suspect the wiring in the '49 leaves a lot to be desired and the last thing you want to do is burn it down because of a cobbled up wiring harness.