It's going to be important to factor in the date of manufacture. If it is pre 76 (and pre ADR 27A) then there's stuff all regulations (relatively) but after that, and the further along you go, the more it will be an issue. If you do an engine swap from a newer engine - then the emissions standards that the motor/donor car was subject to has to be applied, even if the car the modern engine goes into is 40 odd years of age!

Never mind about power increases (of which there usually are none with a pod filter anyway unless there's something drastically wrong with the filter on there before the swap to a pod filter) where it will be a potential issue is emissions. You can't exactly have other stuff being fed into or out of some air filters if teh element is removed and a pod put on instead.

You can also find the airbox size and shape was designed to help smooth out airflow going through an afm, hot wire or otherwise, and the pod upsets it.

If you used an airbox from another vehicle, whilst it might technically lead to NVH or other issues (they tend to be optimised for the specific engine that they are mated to) - but I suspect most engineers wouldn't pursue that angle as hard, and if it has a proper airbox on there, it should be allright

briefly
no cover or one of those half shields over a pod =illegal (sounds better yet sucks in all the hot air from the engine)
vs
an enclosed in a box pod filter is legal.(quiter yet if a decent cai is made provides better results then unenclosed)

forgot to mention airbox , aslong as it has an airbox its legal. from any make , they usually dont care as long as your not running a trumpet straight off your throttle body that has a hole cut out the bonnet hahaha


:)

Just wondering whether anyone has some 'official rules' on the use of Pod Filters.
Seems to be a lot of conjecture around what's legal and what's not.
I called VicRoads and was told 'if it improves the performance of the vehicle then it would require an engineering certificate from and approved engineer to ensure it complies with ADR's.' But when I asked if VicRoads could point me to the ADR in questions he just advised that these are Federal rules and he couldn't assist, would be up to the engineer to determine if a pod filter complies.

Has anyone here had an engineer signoff on the use of a pod filter? Did it have to be fully enclosed?
If not do similar issues apply if you use an airbox of a different vehicle manufacturer?