How long should you warm up 1980 truck engine?

How long should you warm up 1980 truck engine?
When you use petroleum based lubricants and the weather's temperature is below freezing, it could take a while. Using synthetic in the engine and transmission would reduce this significantly as well as reducing the fuel to do it. Sixty percent of the wear in an engine is caused in the first minute and a half, meaning that synthetic engine oil would reduce this wear to a degree that it's life would extended. In other words, operation and maintenance is reduced with synthetic lubricants. Equipment owners who use synthetic hydraulic oils love it because they experience reduced maintenance, start-up time and operation expenses.