6T2Vette

I just had the 327 overhauled in my '62 'Vette. It's missing the down draft tube. I'm wondering if it had one. I have a '66 327 in my '56 Chevy and it doesn't have a down draft tube. I have Edelbrock valve covers on it and I use one of the vent caps to route a vent tube to the Edelbrock 600 cfm 4bbl carb. No PCV valve.
The aluminum valve covers on the 327 in my 'vette don't have any vent caps, so what do I do if I don't want to use a down draft tube? Do I buy an oil filler cap with a vent tube? Where do I route it to if my Carter 600cfm doesn't have a tap for it. Do they sell an adapter for it.? Do I cut a hole for it in the air breather? Is that the breather tube on the intake by the base of the oil filler tube?
Thanks,
Bob

cv67

Did those tubes stop in 68? Maybe thats what you have?

You can drill and tap a hole in the rear of the plenum/runner if need be. If you have room for a spacer same thing.

61corv

6T2Vette

FYI… Note tube outlet right behind fan pulley next to oil filler tube. I don't have it in my later 327.
Bob
PS; Forget it! It's for the heater. My BAD!!!

Abriel Pacheco

Hi guys I'm new to this and I bought this car and it's been an adventure ever since I finally got it started to run the first time I'm 42 years it's been parked went up before I bought it and just that the smoke was burning that smell just everything put in my hands getting dirty getting mad and day and night 3 months in and I've done so much to the car rust you name it still got a long way to go but I'm very skeptical about putting in this Edelbrock 600 cm and the edder block performer and since I bought these new valve covers with the hose I don't know where to start

Finally put the carburetor smoke was coming all through the valves specially from that vent in the back tube

I got this at a rock and I finally realized it don't have the same hose as for the oil tube



That's the same hole

GearheadJoe

As usual, DZAUTO has correctly summarized the situation and provided useful photos. I just want to add one more photo to clarify where the "rear crankcase vent" is on the pre-1968 blocks. It's right next to the distributor at the back of the block, and you can easily see it with a shop light.

This hole was used for the open "draft tube" until about 1963, when the same hole was re-purposed for the PCV (Positive Crankcase Ventilation) system. In the factory setup, this hole was an essential component of the design that used factory-style un-vented valve covers with no holes in them.

65GGvert

His "L" key is sticking, though.

6T2Vette

I rerouted the down draft tube to the back of the carburetor. The back of the carb has two ports. One can be used for vacuum assist power brakes or sealed if not used. The other is meant to be for the PCV system, Caution must be taken when installing the "L" outlet fitting. It is a special fitting with an approximate 3/32 orifice. Failure to use this fitting caused me a lot of accelerator problems.
Bob

TCracingCA

I will actually give the NCRS guys a tip, for accuracy of this build, you might want to do the Dealership search thing, to figure out if it is a California car or not, before deciding on this.

Looking good though! I clean work!

GearheadJoe

It's not clear what sort of valve covers you plan to use, but if you find that you wish you had an oil fill tube like the one in your photo, an easy way to get that is to use this Edelbrock 2703 intake shown below.

Alternatively, there are also zillions of used vintage GM intakes and used vintage aftermarket intakes that have the provision for the oil fill tube. So, if you prefer to retain the period-correct appearance of this engine, you have plenty of options.

Drummer Boy

My car is a 62 with a 66 engine.
I googled on the part you named and it says that the elbow is not compatible with either a 62 or a 66.

I also am having "acceleration issues " since I installed a pcv from the road draft tube to the carb.
Either I have the wrong pcv or perhaps this fitting might solve the issue.

Could you please explain further about your acceleration problems before you installed the fitting 14442? The package says something about fuel injection.
I assume that you have 62----is it fuel injected?

Thanks
Eddie

GearheadJoe

I realize that this question is not directed to me, but I thought I would comment. All PCV systems use manifold vacuum to draw fresh air into the crankcase and pull "oily air" into the intake manifold to be burned along with the fuel mixture. If the connection to intake manifold vacuum is not restricted in some way, it will behave like a giant vacuum leak and the engine will idle poorly.

Early PCV systems used a small orifice to create the desired restriction, but later PCV systems used a PCV valve. These two methods of providing the desired restriction should not be combined.

If you have an unrestricted set of connections combined with an actual PCV valve, the system should work fine unless you have the wrong PCV valve. The various PCV valves are calibrated to the expected intake manifold vacuum of the engine.

If your engine is stock, just make sure that you are using all the correct stock components.

Easy Rhino

LOL

My guess is lllllack of llllllubrication from actualllllly having an oillll filllll tube instead of having to spill oillll down vallllve covers for engines not so equipped.

Drummer Boy

Yes,
I thought I was replying to 6T2---sorry about that.
But your explanation is quite clear. Thanks.
Do you have any suggestion as to the proper PCV for the 327/350.
The Oreily guy sold me one that is supposed to be correct but I have doubts because the behaves like it has a vacuum leak--but I cant find one. The engine idles OK but then periodically hunts---it drops way down then eventually stabilizes. I also have acceleration problem in first and second gear--by the time I hit third it seems to smooth out. The problem is very intermittent.
I am also looking into the intake manifold not sealing properly because I am burning too much oil--1 qt every 4/500 miles. That also seems intermittent --like it is tight for a while then starts sucking. Put a smoke machine to it yesterday but saw nothing unusual.
I am truly perplexed.
Eddie

GearheadJoe

What year is your C2? Is the engine stock (especially the cam)? If so, the correct GM PCV valve (or quality substitution) would be the best choice.

In my experience, an incorrect or defective PCV valve can affect the idle, but not much else. It sounds like you may have some other things going on that are not related to the PCV valve.

6T2Vette

Sorry I haven't been checking in to this forum lately, but thank you Gearhead Joe for providing the correct information on the restricted elbow coming off the carburetor. It solved my stalling problems once I got the elbow with the restreicted orifice.
The 327 in my '62 is a numbers correct engine, but I did swap out the Duntov Cam and domed pistons for a Lunati performance roller cam with roller tipped rockers.
Bob

stevelang

I read this whole thread with great interest. i created a closed pcv system for my 65 corvette 327 using 67 oil fill tube with the screw in pcv valve. i am now working on a 1964 el camino with a 283 and a modern carter afb. it has a later (1979) cast intake sans oil fill tube and wrong valve covers with a pcv valve in each cover. THEY ARE CONNECTED TO EACH OTHER WITH A HOSE. dumb. there is a road draft tube fitting at the back of the block with a hose for a road draft tube that extends down about a foot. not enough for a scavenging wind. i will be replacing the intake with a 3844459 and steel Chevrolet script hole-less valve covers. i plan to build an open pcv system with a vented oil fill tube for the inlet. i want to use the road draft tube fitting in the back of the block. the consensus seems to be to use the cv 590 or v-100 pcv valve with an open 90 degree brass fitting in the back of the carb. this puts the valve at a horizontal. my concern is that the v-10o I have in my hand does nothing at the horizontal. you can put vacuum to either end or blow in either end and it has no resistance. it only works in a vertical or near vertical position. there is no spring so the pintle only closes the valve with gravity. any thoughts on this conundrum?

GearheadJoe

I'm not familiar with the various PCV valves that are available, but it makes sense to me that versions that were designed to be mounted vertically may not have a pintle spring. The CV726 used in 1966-67 small block Corvettes is designed to be mounted horizontally by screwing directly into the side of the oil fill tube, so this style has one end threaded. I *think* the 1965 small block Corvette PCV valve is also designed to sit horizontally, in series with a rubber hose. If so, then both ends of this valve would have hose fittings.

68hemi

65 did not se a pcv valve, it has a.090 orfice in the elbow going into the carb.