look at various constructions of sensors i.e. a cutaway
Depending on the construction of the outer shell of the sensor it has small holes in it to let exhaust gas into to it as long as none of the holes are blocked from gas flow and it doesn't touch the other side of exhaust pipe it should be okay. Also from the exterior wire side air is allowed to go inside the sensor's interior down along the wires.
Note there are different designs, older and newer and some work differently than others look it up in comprehensive automotive technicians book descriptions. Older ones were 2/3 wires newer ones with built in heaters have 4 wires. no hard and fast rule ....evolution.But they were specific to each model car by the manufacturer.
'61 Guilietta Sprint
'69 1750 GTV
'74 2000 GTV
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