200ci Degree the cam?

[pmuller9]

When I slam the throttle the vacuum goes to zero.

Does it stay at zero at 3000 rpm?

 

[Dustyford]

If I leave the rpm steady the vacuum goes back to 18”ish

 

[awasson]

Did the ‘68 200 not have a PCV system? I’m trying to do what people tell me but people are telling me different things.

Not to derail the discussion from the points that have been raised but @pmuller9 but regarding PCV, the 1968 200 definitely had a PCV from the factory and it is important to evacuate the pressure to prevent blowing the seals.

I'm not sure whether you have a performance cam or mild cam installed but the one I am running is said to be a mid-range street cam and I have no problems running a PCV. If you have 18" of vacuum at idle and 18" of vacuum at cruise, you can certainly run a PCV. Your engine is designed to have a breather cap at one end of the valve cover and a PCV at the other. The PCV line should go from the valve cover to the intake log below the carburetor or to a fitting on the spacer below the carburetor.

 

[Dustyford]

Not to derail the discussion from the points that have been raised but @pmuller9 but regarding PCV, the 1968 200 definitely had a PCV from the factory and it is important to evacuate the pressure to prevent blowing the seals.

I'm not sure whether you have a performance cam or mild cam installed but the one I am running is said to be a mid-range street cam and I have no problems running a PCV. If you have 18" of vacuum at idle and 18" of vacuum at cruise, you can certainly run a PCV. Your engine is designed to have a breather cap at one end of the valve cover and a PCV at the other. The PCV line should go from the valve cover to the intake log below the carburetor or to a fitting on the spacer below the carburetor.

I have a rough 14” at idle and 18” at cruise with new mild cam. PCV makes it unable to idle unless I raise it up to 850+ rpm. I have a ‘65 200 with ‘68 carb and distributor

 

[63 Sprint]

A 1968, had a PCV. Someone put a draft tube on it.

Added
My apologies, I overlooked that your engine is a 1965 engine with a 1968 carb.

 

[63 Sprint]

Does it stay at zero at 3000 rpm?

Dustyford, did you do the test while driving on the road?

 

[Dustyford]

Dustyford, did you do the test while driving on the road?

No sir. Static in neutral. I haven’t done any tests while driving except rpm. I don’t have a vacuum hose that long.

 

[63 Sprint]

I have a rough 14” at idle and 18” at cruise with new mild cam. PCV makes it unable to idle unless I raise it up to 850+ rpm. I have a ‘65 200 with ‘68 carb and distributor

Again, Get an AFR meter installed.
If you want to keep the cars appearance stock, you can remove the AFR meter after the carb is tuned properly. The only thing that will not appear stock is the O2 bung welded on the exhaust down tube along with the plug. The O2 bung can be put in a non-conspicuous place.

 

[63 Sprint]

No sir. Static in neutral. I haven’t done any tests while driving except rpm. I don’t have a vacuum hose that long.

You have to get it on the road under full throttle on a full load for a good length of time to get an accurate reading.

Try doing the test in 3rd or 4th gear close to 3,000 rpm for approximately 5 to 10 seconds.

 

[Dustyford]

You have to get it on the road under full throttle on a full load for a good length of time to get an accurate reading.

Ok

 

[Dustyford]

Again, Get an AFR meter installed.
If you want to keep the cars appearance stock, you can remove the AFR meter after the carb is tuned properly. The only thing that will not appear stock is the O2 bung welded on the exhaust down tube along with the plug. The O2 bung can be put in a non-conspicuous place.

Ok

 

[Dustyford]

A 1968, had a PCV. Someone put a draft tube on it.

It’s a ‘65 200 with ‘68 carb and distributor. The draft tube came with the engine from the factory. I changed to PCV after 15 people told me it would be better

 

[63 Sprint]

I believe the draft tube was phased out in 1966. As far as I understand, all street driven 200 sixes were installed with PCV in the U.S. after 1965.

 

[vssman]

A PCV valve is just a metered vacuum leak. I had a lot of trouble setting up my 68 200 and did away with the PCV valve (unpopular option). A road draft tube will ventilate the case just fine.

 

[vssman]

@Dustyford after all is said and done and you running. If you don’t use the road draft tube, I’d be a buyer.

 

[Dustyford]

@Dustyford after all is said and done and you running. If you don’t use the road draft tube, I’d be a buyer.

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