MSD RPM Three Step Module Selector NG278 Holley Ultra XP carburetors are

Holley Ultra XP carburetors are Specifically Calibrated for Circle Track & offer new features such as anti-siphon valve in the main body

Square Port

1959-1965 Fargo F100 Panel Delivery

14mm Thread -

MSD RPM Three Step Module Selector NG278 Holley Ultra XP carburetors areThe MSD Module Selectors allow you to choose two or three different rpm limits that can be activated at different times. With this ability, the possibilities are endless. As an example, well use a drag car with a Three Step Module Selector plugged into the rpm socket of a 7AL 2 Ignition. The different rpm modules are activated when 12 volts are applied to a corresponding wire. By connecting one wire to the line lock circuit, one module will be