I run a small roller also with a partially filled block. It seems the car cools well but watching the oil pressure it seems like the oil is heating up even with water temperatures stabil. Anyway, I wasn't looking for an absolute oil temp but rather a gauge as to what was mentioned earlier with oil pressure and water temps etc. I guess I will try and install it in the oil feed lines going into the heads as there it will have some oil movement and give me some kind of reading.