[James]

I was thinking about your truck today and it occur to me that you might want to dig into the engine a little deeper.

I understand why some people would leave the thermostat out. A colder running engine produce more power. This might be true on a racing engine, it is not true for a daily driver. My truck takes about 5 miles to get it up to normal temperature with a thermostat. It does not like to run when it is cold and sometime I have to use the choke.

If they did drive it without a thermostat don't be surprise when you remove the valve cover (for your routine valve adjustments) that you will find a lot of carbon/sludge build up everywhere. Not allowing the engine to come up to proper operating temperature will not allow the water/fuel to leave the engine oil through the crankcase vent system. If this is allow to continue it will starve the engine of lubrication and then you will start to hear a rod knocking. I recommend removing the valve covers and pan to remove the carbon/sludge (and maybe the camshaft cover too). Then with a new filter and new oil drive the truck about 100 miles and change the filter and oil again.

This is only my opinion. It hard enough to buy parts for it and I like to keep it running.