Hi everyone,
I've got a 68 firebird w/ a 350 in it. She's got a rebuilt Holley 750 and I was wondering. Whats better for performance? Should I continue to run my PCV valve in the valve covers to the manifold vaccum port on the back of the carb. Or should I use an open element breather cap on the valve cover and cap the manifold vaccum port? I don't have any emissions laws to worry about and I want the best performance I can get.
Thanks,
Brian

Hi everyone,
I've got a 68 firebird w/ a 350 in it. She's got a rebuilt Holley 750 and I was wondering. Whats better for performance? Should I continue to run my PCV valve in the valve covers to the manifold vaccum port on the back of the carb. Or should I use an open element breather cap on the valve cover and cap the manifold vaccum port? I don't have any emissions laws to worry about and I want the best performance I can get.
Thanks,
Brian

You will lose ZERO performance with a PCV valve, and you will cut your overall emissions about 80%.

In addition, your oil will stay clean longer, and it will increase bearing life because of less acid/moisture build up in the oil.

The PCV system was the first--and finest--bit of emission control engineering in the automotive world because it is dirt cheap, extremely reliable, and hugely efficient at reducing pollution.

Your engine needs air flow through the crankcase so you should have an inlet(breather) and an outlet (either a pcv valve or a draft tube).

I definitely agree with Schurkey! Ever seen rust on the inside of an old engine without a PCV valve?