Steve, how old a Chevy? Do you want switches or analog sensors? Are
you talking about "vacuum" advance? You will need a pressure sensor/switch.
Sensym and Motorola have a variety of sensors. If by "old", do you mean
1955/56? If so, I might want to buy it ;-)

   - Tom

At 01:24 AM 12/4/97 -0500, you wrote:
>How might I interface a vaccum system to a pic?   Does anyone make
> sensors that can be used to detect various levels of vaccum, like
> some automotive sensors do?
>
>My goal is to replace some extinct vaccum switches and sensors in my
> old chevy to make the system more configurable, and controllable, like some
> of the really expensive performance carb systems do.
>
>Steve
>
>