If you have an HEI distributor with a Tach Output you can use the Tach Output from the distributor. Due to the high voltage of the signal from the HEI you should use a tachometer filter to prevent damage to the tachometer. Coil Pack or Individual Coils (Distributorless Ignitions).
Yes, thyroid disease can affect your mood â primarily causing either anxiety or depression. Generally, the more severe the thyroid disease, the more severe the mood changes. If you have an overactive thyroid (hyperthyroidism), you may experience: 1  Unusual nervousness. 2  Restlessness. 3  Anxiety. 4  Irritability.
1 Some mental illness, including depression, anxiety, and postpartum depression may even be driven by thyroid dysfunction.  Antibodies to thyroid tissue are present in 20 percent of depressed patients, as compared to 5-10 percent of the general population.