<VV> low vacuum findings

[william weissheimer]

Hi Dan,
   Just wanted to share the findings on my 110pg, 64 carbs, 12 deg. BTDC, looks like   
   sbc lifters set at 1/4 turn:
   11" hg @  600 rpm in neutral
    8"  hg @  500 rpm in drive
   Vacuum gauge was attached to balance tube modulator nipple.
   Engine runs well off idle, but does idle rough in drive.
   I thought the rough idle was the result of not having the carbs set up properly as I'm   
   not a Corvair expert. Did do a carb kit and shady tree carb balance with vacuum  
   gauge.
   Maybe worn guides? 
   Valve overlap as stated earlier sounds logical.
   Will