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I have a small block 350 chevy and i was just wondering if i should run a pcv or if i should just use breathers. Are there advantages to either? Also if i run a pcv are they all the same or is there a certain one i should use? thanks in advance.

Thanks,
Matt
 

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dude you're better of asking this in the "engine" section of the board, this is the lounge, a place to hang out and discuss non automotive stuff.
From the little knowledge I have is that if it's a daily driver, use pcv. If it's just a weekend cruiser breathers'll do fine. Maybe I got it ALL wrong, so dont listen to me and go to the engine section.





Mike
 

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It's better, environmentally, to have a PCV to take the internal engine gases and reburn them via the carb.

I don't know why there are a bzillion different PCVs. They're not some highly technical device! All of my stuff is "hybrid" so I choose a PCV that fits an SBC, fits my valve cover grommet, and only has one outlet.
 

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PCV alternative

I've heard that running a PCV can screw around with timming and idle speed, since hooking the PCV valve up to the carb port amounts to a vacuum leak. Another option is to use a breather on one side (for air circulation) and a breather with a vacuum hose running into the air filter on the other valve cover. This way, your blow-by gets evacuated from the case with-out going into the atmosphere and no vacuum issues.
 

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By all means run a PCV. It keeps the engine clean and actually boosts efficiency a little 'cause you are capturing unburned hydrocarbons. You need a filtered air source coming into the crank case (valve cover breather, hose from air cleaner. etc.) and the PCV is hooked at another place remote from the first connection (opposite valve cover, lifter valley) so there is a cleansing flow through the whole engine. Hook the other end of the PCV to a port under the carb in the manifold plenum. PCVs are fairly sophisticated with a check valve that prevents back-flow from the carb into the crank case and also limits the rate of gas being sucked into the intake manifold which would otherwise result in the appearance of a vacuum leak.

One of very few pollution controls that is also a good idea on it's own merits.
 
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