you should have one breather (on the passenger side preferrably towards rear).. two breathers and you will lose the vaccum effect.. no breather means little or no air flow.


I've got a vent on each side at the moment, on the drivers side at the front and the passenger side at the rear. Should I put my PCV valve on the rear or the front? I was going to put it on the rear 'cause it's a shorter route to the carb for the hose and won't get in the way of any carb linkages etc.

Speaking of carbs I have a Holley 600 with manual choke set up. Has anyone seen a auto choke mechanism for a Holey 600(I haven't been on the Holley site yet). I don't want to run a manual choke cable into the cabin.

Chips58 said: I've got a vent on each side at the moment, on the drivers side at the front and the passenger side at the rear. Should I put my PCV valve on the rear or the front? I was going to put it on the rear 'cause it's a shorter route to the carb for the hose and won't get in the way of any carb linkages etc.

we you certainly should not have two breathers..

I dont know any reason why it would matter which side you put the PCV on ..

that being said.. ive never seen one on the passenger side.. always the drivers and maybe one of the pro's here knows a reason..

if it was me.. id assume chevy had a reason to put it on the drivers side front.. and do that.

The PCV valve was opposite from the fill cap. Just easier to build that way. There is no specfic reason to put it on one side or the other. It will work well either way.

my 2 cents: I asked a question about my PCV a month or so ago, and think I FINALLY understand!

On my '79 L48, I have what I would describe as the PCV inlet on the rear of the passenger side valve cover, fed via a hose to the air cleaner assy. Then, on the forward portion of driver's side valve cover is another fitting (the PCV exhaust) with a large hose connected to the base of the carburetor. Together these 2 fittings comprise the Positive Ventilation system.

Now all I have to do is get some nifty valve covers and after-market breathers to really "beautify" underhood!

There you go. You got it. And Chrome is always a good thing.

AzulVette said: Now all I have to do is get some nifty valve covers and after-market breathers to really "beautify" underhood!

This is one thing you don't want to go cheap on either. There's nothing more frustrating than having nice shiny valve covers but having them leak down the side of the block.