HONDA Ventilation Plug. As with all Genuine Honda parts, expect perfect fitment. Fits most Honda engine blocks. This plug replaces the stock allen bolts in the lower block. Replacing these can create another source of ventilation. We strongly recommend connecting these plugs to an oil catch-can. A maximum of 2 plugs can be used on the block at any given time. Sold singulary (1 plug and 1 washer). Part numbers