Hi KeMac
Fuel would normally be in USG (US Gallons) - for comparison we have a 1944 C47 maint manual which states 202 USG each side for main tanks.
The '8' for Engine Oil could be the oil spec - once again in our C47 manual it states 'AN-O-8' grade 1120 (summer)
For the Oil Tank Capacity on the C47 the manual states 29 USG each side,I realise that the C47 may have bigger oil tanks but '8' of anything is not really enough for a large Radial.