What you folks say makes sense but here's the part I don't understand
(sorry - didn't give complete info in my first post):

Aside from the PCV holes, the only other hole is the oil fill in the
passenger side. The cap, which sure looks like OEM, is the screw-in,
NON-breather type - in fact, it has the rubber gasket to seal it to the
cover. The covers and cap were on the car when I got it - took them
off to clean them up and found the rubber parts are toast. Anyway, it
seems to run OK.

Although...it sometimes dies on cold start and it idles a little high -
maybe to compensate for lean mixture? And, I've had trouble with oil
leaks - maybe vacuum breaking the gasket seal?

I was looking for a plug in the auto parts stores but I just remembered
the local hardware store has some polyethelene button plugs that might
work. Sounds like I also may be looking for a breather cap for the oil
fill.


wrote:
> I have a pair of nice cast aluminum valve covers for the '74 Chev
> truck 350 in my street rod. Both have identical PCV holes so the valve
> can be placed on either side depending on application. On mine, the
> driver side has a rubber grommet for the valve and the passenger side
> has a rubber plug. Both parts are too deteriorated to use. Problem
> is, my local Chevy dealer can order the grommet but they have no
> listing for the plug. I've looked for an after-market plug but I
> haven't found one that fits. I really want to use the covers so I'm
> thinking of putting a grommet and valve in each side and connecting
> them to the intake with a "T" fitting. Is there any reason I
> should NOT do this?