Re: '71 &LT1 PCV Valve
Ray,
Just to add more mystery and confusion to this thread, my 1st edition January 1970 owner's manual (for 1970 model) indicates the 350 (non LT-1) "recommends" AC Type CV 736 C, whereas the 350 LT-1 and the 454 the CV 746 C. However, the 1st edition Sept 1970 owner's manual (for 1971 model) indicates the 350 CI engine "recommends" AC Type CV736C, and the 454 the CV746C. There is no differentiation between the LT-1 and other 350s for 1971.
Hmmmm ...
Also attached is a nice plot I came across that depicts the general airflow vs. intake manifold vacuum of a typical PCV valve. I would surmise that the amplitude, shape, and horizontal position of the plot will vary somewhat depending upon the P/N of the PCV valve. The PCV airflow volume at certain manifold vacuums may also (slightly) affect the air-fuel ratio at given part-throttle openings (manifold vacuums).
I am hoping that Duke W. may weigh in on this aspect. At play here may be the ever changing emissions requirements and quite possibly parts de-proliferation (trying to use less separate P/N assemblies in production). We can probably thank John DeLorean for that effort. (sorry, I liked John for his engineering skills, but not management decisions).
Anyway, interesting stuff!!
PCV Valve Airflow vs. Vacuum Plot.jpg
Ray,
Just to add more mystery and confusion to this thread, my 1st edition January 1970 owner's manual (for 1970 model) indicates the 350 (non LT-1) "recommends" AC Type CV 736 C, whereas the 350 LT-1 and the 454 the CV 746 C. However, the 1st edition Sept 1970 owner's manual (for 1971 model) indicates the 350 CI engine "recommends" AC Type CV736C, and the 454 the CV746C. There is no differentiation between the LT-1 and other 350s for 1971.
Hmmmm ...
Also attached is a nice plot I came across that depicts the general airflow vs. intake manifold vacuum of a typical PCV valve. I would surmise that the amplitude, shape, and horizontal position of the plot will vary somewhat depending upon the P/N of the PCV valve. The PCV airflow volume at certain manifold vacuums may also (slightly) affect the air-fuel ratio at given part-throttle openings (manifold vacuums).
I am hoping that Duke W. may weigh in on this aspect. At play here may be the ever changing emissions requirements and quite possibly parts de-proliferation (trying to use less separate P/N assemblies in production). We can probably thank John DeLorean for that effort. (sorry, I liked John for his engineering skills, but not management decisions).
Anyway, interesting stuff!!
PCV Valve Airflow vs. Vacuum Plot.jpg
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