I'm looking for a tach for my Catalina 27's Atomic (Universal) Four.

On E-bay I've found a Faria and a Searay. They both come with no
wiring, but have connections on the back for three leads, as well as a
switch for 4-6-8 cyl, and 12 point(?).

Question is, would these work with my engine? And, how are they hooked up?

Larry
El Cerrito, CA