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I have a 350 with a mild cam, holley 750. I recently purchased a set of Moroso aluminum rail valve covers without holes. Do I need to vent both sides? I'm a gear head in training so don't know the answer. Thanks for any help.
 

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I've been searching for no-hole alluminum valve covers, what moroso part # are they?

As far as venting, don't get me going...lol. I'm gonna find some way to plumb all thing so oil never ever drips on my engine...Yes, you need at least one vent. Alluminum valve covers typically have no or bad baffles, so the vent leaks oil.
 

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Very true about aluminum covers with crapy baffles, I ditched my edelbrocks cuz the baffles are worthless. I would like to add to DREIDs question. Would it be ok to just have a pcv on one side and plug the other cover(if theres a hole)? I would think that would create better vacuum in the crankcase and help ring seal, I never understood the need for a baffle on the opposite side of the pcv.
 

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awww.... now you're gonna get me going.

As I'm TOTALLY sick of oily mess coming out my breathers, here's what I'ma gonna do. First, I'm gonna cut the hole in the front of my intake manifold and put a chrome oil fill tube in it. The tube has a threaded bung in it which will go to the PCV, and I'll use a sealed cap on it.

On the valve covers, I'll use no-hole alluminums, and drill through the side between the rear 2 intake valves. I'll tap the hole for a threaded tube fitting, and run hose into the bottom of the air cleaner. Inside the valve covers, I'll epoxy in some homemade baffles to keep any oil from getting near the hoses. Think I'll seal the holes in my old m/t covers and test on them.

I'm absolutely determined to keep this mess in the engine where it belongs!
 

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oh, and you can't just have a pcv. For one, when it's sucking, the air needs someplace to come in from. For 2, under low vacuam (WOT!) it ain't sucking (much), and the fumes may need someplace else to go.

You could have just 1 breather vented to atmosphere, but that might get messy agian.
 

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Discussion Starter #7
I have a buddy who drilled both cover holes on the back side and connected them together with a pipe and one breather/filter. That is on a bb tempest though and I don't think any camaro could fit that. Just a thought though.
Seriously though, my breather/filter is going to make a mess?
 

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Discussion Starter #9
Good idea - wow our engine bays look similar. I have the polished front runner, too. Very nice!
 

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Was looking through Moroso's website today, they have some that bolt through the valve cover, says NHRA rated for under 7.99.... I bet those don't leak, wonder what they cost?

Really tho, the best answer on a street car will be a closed vent system, with a pcv in one side, and a breather hose into the air cleaner on the other. Trick is to use use something that's properly designed to keep the oil in the engine.
 

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Moroso has 3 "positive locking" brathers that are threaded from the underside of the valve cover. The Moroso part numbers are: 68785, 68786, and 68788. The first two are zinc plated ($50/ea) and the third is billet ($100/ea). Two of the parts have provision for hose/pcv, but no metered valve. As for the closed vs. open discussion: When you vizualize the amount of pressure in the crankcase (remember pistons go up and down. There is pressure being created on the back sides of each piston when it goes down). Add to that any blow-by at high speed and you have a lot of air/vapor with nowhere to go. One breather is fine, but be prepared to have a big mess to clean up especially if you like high-speeeds. A closed pcv system pulls fresh air into the crankcase from inside the air cleaner (before the carb) and draws dirty air through a pcv valve directly into the manifold. An open system would work the same way except pull fresh air through a regular breather on the other side of the engine. Hope this helps.
 

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If you look at the last picture on this page:
Last picture on this page
you will see how I vented my aluminum valve covers.

I bought my valve covers from ebay and they came with baffles and had holes in each one. The oil fill on the left side has a cap with a tube on it. I took some 5/8" heater hose and attached to it. Then I drilled a hole in the botom of the air breather and picked up a rubber 90* grommet from the "Help" section at the parts store. If this draws air from this side it will be filtered by the air filter.

The right side has a standard PCV valve and is attached to the big vacuum port on the bottom of my Edelbrock carburetor.

The holes in the valve covers are the same size so be sure to get the rubber grommmets that are the proper size for what you are attaching to it. The PCV grommet has a smaller hole than the oil fill cap.

I do not get any oil film or drips anywhere!
 

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Supv , this should work but looks backwards from stock... crank vent could go from air cleaner to cover on right side and pvc pick up on left, of course I am comparing with a Holley carb the have the large vac feed on rear of carb too. Just my 2 cents
 

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Supv': Good "closed system." Nice not to have to clean up oil all the time. Zdld' you could run from the other side and it will work the same way. An open system would have a regular breather in place of the one on supv's left vlave cover (no hose).
 

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In my shopping recently, I've seen a number of alluminum covers claiming to have "factory style baffles and oil drippers" Anyone have experience with such things? Are we talking something better than those peices of tim they give you to screw on under the holes?
 

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All factory finned Z or HP covers (ones with flags) did not have drippers yet lots of people want them over the ones that do,, It just makes sense to have the drippers, As for aftermarket,, I dont think you will find any that do, or I havent.
 

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JimM,

If your motor is an old style one with the draft tube boss back by the distributor, I would set it up with an older intake that has an oil filler tube and push-on breather cap and then use the stock, non-Cali. type pcv system on it.

This consists of a small sheet-metal bolt-on cap that bolts into the draft boss. It has a hose fitting on it so a short length of rubber hose with a pcv valve in the middle of it and then another short piece of hose to the carb. base can be mounted like stock.

You will never have oil on your valve covers again!!

Your valve cover gaskets might leak, but NOT on top unless you spill some oil on them!!

I still have my OEM, 350SS chrome hole-less valve covers in case I ever want to hunt up a correct '67, 350 block and re-pop my 350SS motor..

pdq67
 

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I wish, Paul, but my motor's a year to new, no draft tube. I did drill out the front of the manifold, and put in an oil fill tube with a boss for the pvc, so that end is done. Now I just gotta get an air inlt somehow.

Thinking bout just sealing the leaky holes in my m/t covers with some fender washers and jb weld for now, and drilling and tapping for a fitting in the back somewhere, rigging some sort of baffle, and running hose from there into the air cleaner base. See if I can come up with something that'll work, and then spring for new covers. I really like the old style edelbrok finned covers, but they come with no holes, no baffles, and a hunert and fifty clams...
 
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