I a pair of P5007614 cast aluminum MP Valve Covers. They have a feature for breathers or a PCV valve. I want to put a PCV one side and a Breather & Oil filler cap on the other side. A few questions they have what someone called a knockout on each side. Can this be punched out or does this need to be drilled out? and explain? Second question MP makes a valve cover grommet MP #P4529882 dimensions (OD 1.22 inches) (ID 1.00 inches) Do I want a breather or PVC with a 1.00 inch OD inch push in tube? Also if I drill out the valve cover for the grommet what diameter should it be? Thanks everybody.

The knockout areas are obviously on the right hand side in your picture. The casting is thin in those areas. They can be punched out. You don't have to drill. You'll need to clean up the edges with a file though.

Depending on where you want to place the breather and PCV, you may only need to punch out one hole. I used a breather that screwed into the oil cap hole on one side....and punch out a hole for the PCV on the other side. Just plan out where you want things before you knock out the holes.

I would use a hole saw with a pilot bit to cut a clean hole. measure your rubber gromet for hole size. needs to be able to hold the gromet and not weep/leak around the VC edge.

if you knock it out it could make the hole to large as the thin area will all want to break off. but I have done it that way more than a few times.

I fitted a PCV valve on the driver's side. I drilled and filed the hole to fit the grommet. On the passenger side I fitted a breather in place of the supplied filler cap. The baffles are fitted with self tapping screws, use loctite on the screws so they don't come loose.

Great ideas. I have to figure what size hole, I need to drill in the knock out area. If I use one of the pre-existing, screw in holes, say for a screw in breather, what size is the screw in breather tube diameter, if anyone knows?

That's a push in he was offering to using the screw in cap hole. I think the screw in are pretty universal bit I could be wrong. Had a dodge truck with a Ford breather once

Maybe a little OT but some good info I found when searching info about "big cam" PCV valves
http://forum.grumpysperformance.com//vie...acuum+PVC#p5328
Gus

If you don't need to keep the look factory, you can use the Ford oil cap that has the PCV built in.

This is what I have on my RC with the 440.

No room for the PCV valve to clear the brake booster in my case.