Stock breather with cast MP covers?

[challenger_affair]

1) Is there any functional reason to replace the original stock breather, do they go bad?  If not, is there a specific grommet that will allow it to work with the cast MP covers?  The existing grommet seems to have gotten torn up on the sharp edges of the cover inlet; may not be quite the right gromment for that combo...

2) If the breather is replaced, I notice the replacements do not have the 2 smaller barbs for the fuel tank vent line and the other small line that goes to the carb; are those 2 smaller lines needed or can they be plugged without problems? 

Thanks much! 

[LAA66]

 I'm not exactly sure about the MP but most of the cast valve covers use a wider grommet gap fitting it between the aluminum casting. Take some measurement or both items to the auto parts and they should be able to set it up. And then get an extra for later on.

 As for the ports on the breather i have the tank and air cleaner vent in use with the third blocked off. 

[Barracudadan]

Try this out http://chucker54.stores.yahoo.net/mopcasvalcov.html The breather grommet fits nice on my MP valve cover. My MP`s have a twist on stlye opening for the breather, the grommet from Mancini allows me to use my stock push-in style breather. FYI if you need the pcv grommet for the other valve cover that took a bit of modifying to get in the other cover and was a pain in the azz! You get both grommets when you order it.

[challenger_affair]

Thanks for the suggestions!  I'll give it a go.  Is it safe to assume then that replacing the breather itself isn't necessary unless its obviously plugged or something?