Oil Bath air cleaners
CW, both my TEA20 (Grey Fergie) and my 1937 Plymouth have oil bath air cleaners and both have the cleaner located higher than the carby. The Fergie uses an up-draught carby with the air cleaner remotely located with an air trunk to the air inlet on the carby and the Plymouth a down-draught with the air cleaner sitting on top, as was your Holden. Both are easily "flooded" if the applicable starting technique is not used.