Join Date: Mar 2002
Location: Austin, TX, USA
Re: Orignal 69 tach with HEI, will it burnout
They can burn out. In particular there is a diode and a special transistor inside called a UJT. Back in the day, semiconductors had relatively low specs on peak voltage and current. A tach filter is a good idea to help reduce the amplitude of the signal from an HEI or solid state ignition. However, there are plenty of folks who have done nothing and had no problems. IMHO, better safe than sorry - I recommend a filter.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI