From: muratlanne@gmail.com   
      
   "Snag"  wrote in message news:vfg0iq$35k3b$1@dont-email.me...   
      
      The only control on this one is a vacuum switch . It can be tested   
   with a vacuum pump and a volt/ohm meter - if I knew which wire went   
   where . I haven't done much tuning , I was waiting until I had the drive   
   train in it's final configuration .   
   Snag   
      
   ----------------------------------   
   In case you or some other reader doesn't know it, intake manifold vacuum is   
   an easily accessible indication of the combined accelerator/throttle   
   position and the load on the engine. It's high when cruising at a light load   
   that allows more distributor spark advance without knocking and torque   
   converter lockup.   
      
   https://help.summitracing.com/knowledgebase/article/SR-05127/en-us   
   "Under a light load and part throttle conditions, timing can be advanced.   
   This improves throttle response and makes the engine more efficient. It also   
   helps the engine run cooler. The vacuum advance provides this benefit BEFORE   
   the Mechanical Advance provides Total Timing."   
      
   I've been in the GM lab with the "flow bench" for testing carburetors but   
   didn't have a chance to learn about it, the machine I had built and was   
   setting up simulated faults in the 12V power supply to a fuel injection   
   computer.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)