Hot Rods Rear Main 1st Gen 392 Hemi

When you get a chance, pull the top off of the breather as gimpy suggested and see if the cap actually seals to the body or if there are small lugs that keep it elevated and actually allow air in/out. If the cap seals to the body then we will have more discussion; if it has 'vents' and 'breathes' then you will need to design/install some sort of barrier so that it does not vent/breathe. As suggested, if you remove the cap and shoot a couple of photos then we all can see what you have.
I am not sure if this has been asked; do you actually have pcv valves in each of the lines (to the carb bases) ?

 

Most likely a symptom of the improperly vented crankcase. Get the PVC system working & that should clear up. A guy with a 318 lost his vented cap & replaced ir with a solid cap, promptly blew out the back seal. I had to tell them to get the right oil fill cap.

 

For the same reason as George mentions above, this is why you also see vents used on transmissions and differentials. Not as complicated as a PCV system but still there to keep a pressure build up from pushing lube past the gaskets and seals.

 

Car is in the body shop, but I should be able to get there tomorrow for pictures.
Ground covered with snow, and roads still in pretty bad shape. Us Southerners not to prepared for snow ️.

Geezzzz.
Looks as though I have barking up the wrong "leak", so to speak.
Someone give me info how to attack and resolve this issue of too much engine pressure?
Remember, you will be giving instructions to a verry jack leg. Keep it simple .
Geez

 

Never considered adding PCV to be complicated? Install PCV, run hose to carb, zap and done.

 

Here's another diagram to study.



In this example the fresh air enters thru a hose in the air cleaner. Note that it's listed as "filtered air". Not shown so clearly is that where the hose connects to the air cleaner housing there is a breather element or filter to keep dust and dirt from being drawn into the crankcase. Sometimes the hose comes up into the bottom of the air cleaner on the inside of the filter element which will also provide clean air to the c/case. When necessary this hose can be replaced with a vented v/cover breather or a vented oil filler cap, either with some sort of filtering material.

To provide for a more thorough scavenging of gunk from the c/case, the vacuum supply hose is usually, but not always, connected to the opposite valve cover. In this way the fresh air is drawn from one side of the engine to the other to more effectively remove contaminants and prevent pressure build in the c/case. Actually, when working properly it should put the c/case under a slight vacuum.

If you're working with an inline engine or don't want to clutter up the valve covers with holes, hoses or caps there are other ways to route a PCV system. Some engines put the PVC valve at the back of the engine thru the lifter valley pan and pulled in fresh air thru a vented oil filler cap at the front of the engine. But the idea is the same either way. You ideally want to draw fresh air thru the largest possible area of the c/case (side to side or front to rear) rather than just thru one valve cover or other small area.