Guest Anonymous Posted July 31, 2001 Share Posted July 31, 2001 My '71 z has a chevy 327. It needs new valve covers because the cheap dress up kit covers don't seal. Can someone explanin what is the best set up for the street. My understanding is that the valve covers need to breath. So I'll need at least breathers. Should I go to the extent to run plumbing from my valve covers to the headers? Is it worth the effort and expense. Or am I wrong and can I skip breathers all together? Quote Link to comment Share on other sites More sharing options...
Mike C Posted July 31, 2001 Share Posted July 31, 2001 What year is your motor? Does it have the fill tube on intake with PCV? Fill tube with road draft? If it has the road draft, I'd welch plug (freeze plug) it and run valve covers. PCV in one and vented breather in the other. I like the Wysco cast and polished aluminum tall valve covers from Jegs for $45 combined with the rubber gaskets that should end your sealing troubles. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted August 1, 2001 Share Posted August 1, 2001 I have those valve covers and they are very nice. The only thing to be aware of is that you may have to trim them to fit next to an aftermarket intake manifold like the Weiand Stealth, which I have also. Davy Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 1, 2001 Share Posted August 1, 2001 You don't need to run breather hoses to the headers, they do that on max performance engines (I've seen it mostly on econorails) to draw the blow-by and pumping pressures out the exhaust in a venturi effect. For most street/strip engines its not required IMHO. You could run a PCV valve, or just run filtered breathers. If its a maximum performance engine I have seen a article that using a vacuum pump to draw pumping pressures out of the lower end can net as much as 25hp, but IMHO that would be when your scrounging for the final few ponies out of an engine. Just a opinion. Regards, Lone Quote Link to comment Share on other sites More sharing options...
DavyZ Posted August 1, 2001 Share Posted August 1, 2001 Lone, I totally agree with you. It is way overkill for a street car. Much easier running some breathers like you said. Davy Quote Link to comment Share on other sites More sharing options...
pparaska Posted August 1, 2001 Share Posted August 1, 2001 That hole behind the distributor hole on those 327 blocks connects to a passage that opens up in the back wall of the lifter valley. A "tin can with a pipe on the end" looking thing fits the pipe end into that hole. It bolts down to the valley bottom. There's a little cone shaped piece with a hole in the middle/top for a bolt to go down into the block to hold this piece in. The cone has a pipe coming out the side of it. An inline PCV valve is connected to this with a hose, with the other end of the PCV connected to manifold or carb full vacuum. Yeah, if you still have the can, get rid of it, put a 1-1/4" freeze plug in the hole behind the distributoy, and use a PCV valve in one valve cover, and a breather in the other one. I used a breather that conects to the air cleaner base. The ones that have holes in the bottom seem to always drip oil. Supposedly the MOPAR breather is very good at separating the oil out of the vent stream to the air cleaner. Quote Link to comment Share on other sites More sharing options...
Mike C Posted August 1, 2001 Share Posted August 1, 2001 Stick with one breather and the PCV, although you are drawing in a little contaminated air, the negative crankcase pressure does wonders helping to maintain the ring seal, especially at higher rpms. Besides, it is environmentally friendly and less than $5. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 1, 2001 Share Posted August 1, 2001 Thanks guys! That's what I was wondering. Quote Link to comment Share on other sites More sharing options...
Datsun660z Posted August 3, 2001 Share Posted August 3, 2001 DavyZ Its not the valve covers that have the fit problem, with the stealth intake. It is the intake at fault the instructions that come from Weiand say to use special felpro gasket ?#somthing? extra tall gasket. not Flaming just passing along info. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted August 4, 2001 Share Posted August 4, 2001 I appreciate the info, but there were ever any instructions that came with the intake or any information regarding using any specific gaskets. I will call Weiand and see what they say. Thanks for the information. Davy Quote Link to comment Share on other sites More sharing options...
pparaska Posted August 4, 2001 Share Posted August 4, 2001 DavyZ, I had this same problem with my Holley Contender intake and Moroso cast valve covers. I just filed the valve covers a little bit on the edge to clear it at the intake ports. Quote Link to comment Share on other sites More sharing options...
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