PVC placement on early 1966 350hp

[Nick Mesich]

I am in the process of slowly trying to bring my car back to the way it left the factory. My 1966 L79 car #905 (Sept. 15, 1965 build date) does not have a PVC valve. The carburetor was replaced by a previous owner with a manual choke unit(incorrect unit).

I have found a correct dated 3367 carb and will have it rebuilt and will be installing it this fall, however in pictures of supposedly correct engine compartments, I have seen that a hose runs from the back of the carb (right side)to the Oil fill tube with a PVC valve inline screwing into the tube.

My Oil fill tube has no provision for a PVC valve to be attached. Has it been changed with an incorrect unit or is this correct? Would anyone know which is the right one for this year?

I would appreciate if someone had some pictures of a detailed engine compartment from a properly restored car. It would really help me in my adventure.

Many thanks,

Nick Mesich

[Joe L.]

Re: PVC placement on early 1966 350hp

Nick-----

I amnot aware of any 1966 Corvette small block applications that did not use the line from the carburetor base to the CV-726C PCV valve threaded into the fitting on the oil filler tube. Your car is a very early car, so it's possible that there was some difference at this point. I'm not aware of it, though.

[William V.]

Re: PVC placement on early 1966 350hp

Nick

The 66 300 had a black oil filler tube and cap with a screw in PCV and the 350 hp had the same tube and cap in chrome.

BV

[William V.]

Re: PVC placement on early 1966 350hp more info

Nick

I bought my My 66 300 in 1972. It was number 668 and had the black tube with screw in PCV.

BV

[Michael H.]

Re: PVC placement on early 1966 350hp more info

I once owned unrestored # 00616 and it too had the valve in the filler tube.

[Rob A.]

Re: PVC placement on early 1966 350hp

Nick,

My '66 350 HP engine compartment is all original, with the hose you mentioned from the #3367 carb to the PCV valve, which screws into the chromed oil filler tube. I'll be glad to email you a picture if you give me your email address. The original PCV valves are on ebay quite often if you need to find one.

[Peter L.]

Re: PVC placement on early 1966 350hp

Nick - I think everyone agrees that the PCV should be there, now we'll need to know that the intake manifold is on your '66 small block is correct So what intake manifold is on the engine? If you have the correct intake manifold for the engine, the fix might be as easy as getting the correct oil filler tube for the engine and the PCV. Let us know and I'm sure someone will step up. Pete

[Nick Mesich]

Re: PVC placement on early 1966 350hp

Thank you to all who have responded.

The Manifold looks stock. Has a Winters insignia and number as follows:
3890490. Is this correct?

The Carburetor that is on the car is a Remanufacturered Holley 66-3310.
What is the proper application for this carb?

What a great site!! The support is fantastic. This is one hobby I know I won't feel alone and stranded when I come upon issues.

Regards,

Nick

[Peter L.]

Re: PVC placement on early 1966 350hp

Nick - That's the number (3890490) so the intake manifold it correct. I think most places like Long Island , Paragon, etc. and maybe even GM still have the oil filler/PCV tube. So pop the old one out and replace it. Be sure to check the orientation so the PCV comes off at the correct angle and you should be set. Have fun. Pete

[Nick Mesich]

Re: PVC placement on early 1966 350hp

The current Oil fill tube is loose in the bore.

When I replace it, is there a gasket at the bottom?

Do I need to use a sealer or gasket cement RTV etc. to hold the new Oil fill tube in place?

Thanks,

Nick

[William C.]

Re: PVC placement on early 1966 350hp

Proper tube should be a tight fit in the bore if intake is undamaged.

[Peter L.]

Re: PVC placement on early 1966 350hp

Nick - As Bill indicated, the correct tube should fit firmly into the hole, but since the tube in there now is not correct, it hard to tell what the situation is, i.e. is the tube end smaller in diameter than the correct tube or is the hole somewhat enlarged. There is no gasket. I don't think they used any sealer originally, it was metal to metal. If the new one is loose in the hole, you might be able to enlarge the diameter of the tube with something like the tool used to round/expand muffler/exhaust pipes. Pete

[Joe L.]

Re: PVC placement on early 1966 350hp

Nick-----

The interference fit of the oil filler tube and the intake manifold is a "one shot only" sort of thing. That means that once the filler tube is removed from the manifold for any reason, it will not be a good fit if re-installed, as-is. Sometimes you can "knurl" or otherwise distort the lower section of the tube (where it fits against the manifold bore) in order to re-establish a proper tight fit. In this case, this tube has been previously removed and re-installed. Apparently, it was removed from another engine and installed on yours, since it's the incorrect tube if it has no PCV fitting.

The best plan is to purchase a new reproduction tube and install it CAREFULLY. Like I say, this is a "one shot deal". If you get it in crooked, it will get loose subsequently. You've got to "get it right" the first time. Or, buy yet another tube and start all over again.

[Clem Z.]

if the hole in the manifold is enlarged

get the "green loctite" # RC/680 as this will close up to a .015 gap

[Donald M.]

Re: if the hole in the manifold is enlarged

Or you can use a legnth of 1 1/2" Poly-Vinyl Chloride pipe as a filler tube and thread your PCV into it.
Sorry, the devil made me say it!.
D.