Clearance for RPM Air Gap...

[7milesout]

That's good info. I'm no expert on engines. I'm learning as I go along. It would appear to me that the PCV is on the driver's side and plumbed to the vacuum port on the front bottom of the carb. It also seems as if the passenger side valve cover is a breather, but it is plumbed to the air filter base. So, I would think that's pulling vacuum too.

I'm going to take pictures of both of these tonight and will attach in here tonight or tomorrow.

 

[Frnknsteen]

That's good info. I'm no expert on engines. I'm learning as I go along. It would appear to me that the PCV is on the driver's side and plumbed to the vacuum port on the front bottom of the carb. It also seems as if the passenger side valve cover is a breather, but it is plumbed to the air filter base. So, I would think that's pulling vacuum too.

I'm going to take pictures of both of these tonight and will attach in here tonight or tomorrow.

Well, yes and no. Think of it this way..... The PCV valve is connected directly to the vacuum port, so it is pulling directly through the PCV any time there is engine vacuum. The breather is connected to the ail filter, but is much smaller than the overall air filter, so air can be drawn through the air filter by the carburetor, without the whole draw being on that breather hose. I guess what I'm trying to say is that the draw on that hose to the air cleaner will have MUCH less draw on it than the PCV and it allows air to move either direction as needed to keep the crankcase in a neutral pressure.

Basically, if the crankcase needs air, due to heavy draw on the PCV, it can draw filtered air from inside the air cleaner as needed. Under acceleration, when vacuum drops, and nothing is being drawn out of the PCV valve, any blow-by in the crankcase can still vent out through the breather and/or PCV valve as needed. It just helps the air move in or out of the crankcase as needed, but if you connect them both to direct vacuum, it won't be able to pull air into the crankcase to balance what is being drawn through the PCV valve.

 

[7milesout]

Frnknsteen - That was a really good explanation. I totally get it now. Much appreciated.

While sucking heavily from the PCV side (like cruising the interstate at 3,000 rpm and a small throttle opening), there needs to be a "relief" somewhere that will free up the PCV to work as intended. Otherwise it's like sucking the air out of an empty bottle. Once you've suck so much air out, it begins getting difficult. But with a small hole somewhere else in the bottle, you can keep sucking air through it.

I'm going to go the Scummit website and try to make sure the drop base has a port for connection.

 

[famous bob]

I hate to pull that hood insulator off. I prefer to keep it original. Besides a drop base filter, would you guys pull that insulator off?

I`d remove it in a heartbeat, looks like it is deteriorating anyway.

 

[Frnknsteen]

While sucking heavily from the PCV side (like cruising the interstate at 3,000 rpm and a small throttle opening), there needs to be a "relief" somewhere that will free up the PCV to work as intended. Otherwise it's like sucking the air out of an empty bottle. Once you've suck so much air out, it begins getting difficult. But with a small hole somewhere else in the bottle, you can keep sucking air through it.

Exactly!