this parts diagram show the t stat #19 ,above that are the water cover that covers the t stat also. Notice the bulge in the lower part of the water cover that surrounds the t stat.They are tricky to install due to space limitations. The water cover portion that covers the t stat is below the top edge of the lower motor cowl. Slide the water cover and gasket (once you have put sealant on the head and gasket surfaces) in over the t stat. I have also removed the hood latch to give a bit more room. But you may have to shorten the cover latch bolt a bit to have enough to get it rethreaded again.
It is a tight fit with limited room to work.
"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson