I'm putting together a 67 SS350 motor in a completely stock setup. I'd like some information on the crankcase ventilation.

The 67s have no holes in the valve covers. There's the ventilation hole at the back of the block next to the distributor hole and the threaded PCV connection on the oil filler tube. I'm wondering exactly how these things were set up by the factory. Pictures would be very helpful. Mine is a non-smog engine.

Anyone with a stock 67 350 that can help? Or could someone point me to some detailed information on the web?

Thanks.

 

the vent at the back of the block had a tube that bolted to the block and went to the air cleaner and the PCV had a hose that went to the carb.
hope that helped a little

 

Thanks for your reply. The 67 SS350 motor doesn't have a connection point on the air cleaner or valve covers.

 

then you must have an aftermarket air cleaner. if so then they sell a fitting that bolts to it

 

Nope. No aftermarked air cleaner. The original SS350 air cleaner has no ventilation connection. If there's anybody out there reading this that has an original 67 SS350 setup I could use some clarification on this.

I know that the parts I have for this motor are correct. What I don't know is how the crankcase ventilation is set up. I know that the hose from the PCV on the oil fill tube goes straight to the front of the quadrajet carb. I'm not sure where the one from the back of the motor next to the distributor goes.

I appreciate your help firebird69racer but I've read that this motor is something of a "tweener". Some qualities of both the earlier and later engines. There's no connection to the air cleaner. The diagrams I have are unclear as to the routing and, as you can imagine, any pictures I have don't show anything due to the location.

 

If you are using a PCV valve, the valve has to be connected to a high vacuum port to suck the fumes out of the crankcase, the rear vent has to connect to a clean air supply to allow air into the crankcase.

The hose from the PCV valve should go to a high vacuum point on the carb or manifold. The line from the back of the engine should go to the engine air intake, preferably between the filter element and the carb, usually at a fitting under the air cleaner. If there is no fitting you need to put one in, otherwise you will be bringing dirty air into the crankcase and cause undue wear.

Really old engines had a draft tube at the rear of the engine that exteded under the buttom of the car, and air breathers with filters on top of the valve covers, and no PCV. The idea was that as the car moved, the draft tube would suck the fumes out of the crankcase, and the valve cover breathers would let fresh air in. Not too good for pollution.

 

That all makes sense and corresponds with how the system is supposed to work. That's why I'm asking for someone who actually owns one of these setups to tell me what their "correct" setup looks like. The air cleaner has no connection and I'm not going to drill a hole in a stock part without verification.

I appreciate the help. I really need to see a factory original setup.

 

Wow, this was almost 4 years ago. I saved a link so I thought I'd come back a clear this up.
There were 2 methods Chevy used for crankcase ventilation that I've seen. My own is without the PCV screwed into the oil tube. The other style does have the PCV screwed into the oil tube.

Without: At the back of the block the crankcase ventilation fitting connects a tube from the fitting to the carb base with a small pcv in about the middle. A small bracket holds the pcv and is bolted on the right rear corner of the carb base. The carb pulls air from the crankcase into the engine for combustion. Outside air enters the engine through a ventilated oil cap. This cap pushes onto the tube (no seal) and has a wire mesh inside with small holes encircling the bottom of the cap to allow air in. A factory sticker on the cap would indicate to clean the cap every so many miles.
With: The other type has the pcv screwed into the oil tube with a hose going straight to the base of the carb. The oil cap twists on and seals. This one should have a hose going from the back of the block to the base of the air cleaner. I think these were primarily used on California cars with the smog setup. Not sure about that. But there are two distinct setups.
Mine has no connections to the air cleaner or oil tube. The other setup has both. It took a lot of searching to find the answer to this. In most pictures of factory setups this stuff is obscured so it wasn't easy to find. I wanted a stock setup because my car is a restoration. Thanks to those that tried to help.

 

I was gonna say "holy crap who brought back a 4 year old thread"? Since it's yours, I guess you didn't break any laws.
Glad you got it sorted out, and maybe save someone else four years of research!

 

I thought the same thing. Four years later your still a newbie. At least give us some pics of what the heck is going on.