351 valve cover breather

The PCV valve should be hooked up to a vacuum source below the carburetor. The vent should just vent into the flame arrestor. The PCV will create some negative crankcase pressure in higher vacuum situations thus getting rid of your excess underhood fumes.

You can pipe the PCV into an intake runner that has a port. Some say that may make said cylinder run a little lean but you would have to trial and error it. To stay on the safe side you could get a base plate that has a port in it or a carburetor with a port in the throttle body.

Pretty simple solutions. Also, if the valve hasn't been serviced lately I would pick up the correct stock PCV.

Correct Valve

Here's a picture of what Zach is saying. It's a mid 70's PCM. from an old thread here on CCF



The drivers side valve cover has a PCV valve in it with the black hose going from the PCV valve to the carburetor spacer or alternately a fitting on an intake runner right behind the carburetor. Normally the manifold has a pipe plug in it that you'd have to remove and put a fitting for the hose into the hole..

The oil fill cap has a right angle fitting in it with the reddish hose hooked to it and connecting to a fitting on the spark arrestor.

That's the original setup on a 76 PCM 351.

There were slightly different variations over the years on the oil fill cap/breather setup but the flow path was the same

The red hose color isn't original but you get the idea

Their should be no reason for a valve cover breather you do not have any positive crank case pressure

Thanks for all the info! I've ordered a new carb spacer with port for the PCV and new breather with port for the arrestor. I've been running the boat for so long now with the breather just venting into the dog house that i'm hoping this set up really makes a difference. Thanks again for everyone's help!