Tuning 1979 GTB- Want to hook a tach up in engine compartment while tunning/adjusting Webers. What's the temporary wiring for the tach- with two coils? Tach on dash may indicate on the high side. Dial rests at 500 RPM when ignition off. Temp tach may confirm dash accuracy. Need to confirm 900RPM for idle airbleed jet setting. Thanks.
Just use the "-" terminal on either one of the coils and the "4 cyl" scale on your meter. PS 900 RPM warm idle is the low end of the spec -- should be 1000 +/- 100 RPM at warm idle.
