my dart block has a 1/2 NPT plug at the top rear of the block. the manual says this is a port for a return line on a dry sump setup. my question is, if i remove the plug is this just an empty dry hole that dumps the oil back into the pan, or, does it have heated engine oil running through it so i can place the oil temp probe there? thanks Dave

Dave,

Probably the best place to measure oil temperature is in the oil pan sump. Not sure if your pan has an extra port or not.