I have a 72 Dodge D100 and I want to put aftermarket air cleaner on. Factory cleaner attaches to engine with three air hoses, what do I need to do with those?

 

The vacuum lines will need to be disconnected from the air cleaner and plugged to prevent a vacuum leak. If your still using a carburetor with an automatic choke make sure the choke pull-off stays connected.

A larger hose may be running from the crankcase breather. Your aftermarket air cleaner may or may not have previsions for this. The breather itself should have a filter in it so I don't think most people connect it back when using an aftermarket cleaner or they switch to an aftermarket breather. Just be sure not to plug off the crankcase breather.