Hi Jeff,
You should have good results by goung into the water jacket on the engine. There is all kinds of fittings to hook it up. I don't know right off the size, by maybe someone else will know. Actually, you should get a better reading off the block, because the access on the thermostat housing is for other sensors that controls other devices I think. Someone correct me if I'm way off base.
Truck Tinker from Talking Rock
