MMI Thermostat, 160 degree (late model double-acting)
Specifically designed for the late model Atomic 4.
This thermostat is basically designed as a replacement for the original Holly “three spring thermostat”. The unique conical design of its main valve simultaneously begins to attenuate the flow of by-passing water as the thermostat opens to allow the flow of hot coolant to flow up from the block and head. This makes it a true “double-acting” thermostat. This design also eliminates the need for any additional restriction in the by-pass loop.
In both fresh water cooled and raw water cooled systems, temperature will typically settle in between 170 to 185 degrees depending on the overall condition of your cooling system, the capacity of your heat exchanger, and the temperature of the raw water. We recommend this thermostat if you like to operate your engine at a slightly higher temperature range (raw water or fresh water cooled).
Like the original Holley, this thermostat is designed to work with a standard late model thermostat housing with no need for a spacer. If you chose to use a spacer for any reason, be sure to mount this thermostat on top of the spacer. If there’s already a manual valve in your bypass loop, you can also leave it installed and simply place it in the open position.
Manufactured in the USA