<VV> Positive Crancase Ventilation

[N2VZD at aol.com]

Shortened answer  :64 up (164 cu in) motors had a metered orifice in  the 
pipe to replace the PCV valve. some people have modified this by drilling or  
converting to a changeable jet , like main metering jet from a  carb.       
In theory , you need to change this  factor when making mods to bore , 
carbs , or exhaust etc.
some ideas are at:  _http://www.persh.org/Corvairs/PCVsystem.htm_ 
(http://www.persh.org/Corvairs/PCVsystem.htm)    , among other reading on the subject 
, such as in the shop manual.
regards, Tim Colson