I want to install an aftermarket temp gauge and am wondering where the best place to put the temp sensor. Am currently looking at mechanical gauges, and will be hooked up to a 305 TPI ('86 IROC).
TIA
James

I put in an Autometer 2-1/16" mechanical gage earlier this year, mounted in the A-piller gage pod. I put the sensor in the front of the intake manifold, where the cold-start injector switch USED to be. This location is right next to the engine coolant sensor, so your gage should read real close to what the ECM sees.

Mine does, works great, looks good. May have a picture of it.

One word of caution, the supplied 6ft cable barely reaches the intake manifold, so must use care when routing the cable. IE don't make sharp bends.