What CD box are you using with a Mallory Unilite distributor. I tried a HiFire box but it was not compatible with the factory tachometer.

Which Hi fire? I have one running on the uni lite and the tach out line runs the factory TACHOMETER on my 75 914 OK

I don't remember, what Hifire are you running? What wire from the box did you hook up to the tech? Are you running a tack adapter? Thanks.

I have the Mallory HIFIre VI al (rev limiter)model and the Unlit distributor for the trigger. The yellow wire is the tach signal and the coil has multiple pulses. NO tack signal buffer in use
https://documents.holley.com/6852m.pdf

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Thanks for the information!