I'm thinking that a MAP sensor would do the trick. I'm going to check this out on one of my cars. The air flap measures the air flow which translates to engine load which is vacuum.

A Freescale MAP sensor MPX4100A measures pressure to 14.7, no boost allowed.

www.freescale.com

The output signal may have to be scaled since idle on our cars is .7 volts output from the potentiometer wiper. An op-amp or a transistor could be used.

Does anyone want to chime in on this?

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.