160°F Drilled Engine Thermostat - Indmar LT1 & 5.7LRestore proper engine operating temperature with this 160F drilled thermostat designed for Indmar marine engine cooling systems. Built for consistent flow and reliable regulation, this thermostat is commonly used on LT1 engines in the top housing and on 5. 7L closed cooled engines. The drilled design helps maintain steady coolant circulation to reduce temperature spikes and promote stable warm up characteristicsideal for service replacements and