I thought I'd find this in the tech archives, or under resources, but can only find that it takes 5qt/4.7 litres oil... but not what type.
Nice sale on for a 5 litre jug of Quaker State (40% off) 5w30, 10w30 and 5w20... was going to buy a couple of the 5w30 for my Chev Impala, thought I'd grab some for the '47 Dodge as well, since the oil has been in there probably 20-30yrs. Just not sure what kind it takes.
Figured when comes time to fire it up and see if it turns over, probably best to have new oil/filter.