Alright so I have the HSR setup on my car, and I have one open hole for a coolant temp sensor. Problem is I have the sensor for the ecm, but then the one for the fans. IS there another place I can route the fan sensor to? Someone told me into the water pump.

no holes in the heads?

Which ones are okay to do so?

should be a 1/2 or 3/8 NPT hole in each head under the exhaust ports that go into the coolant.
Driverside between 1 and 3, passengerside between 6 and 8.