Oil Temp Sender

[bren]

VDO make a dipstick sender.. replaces the stock stick and has wires coming off it... i use one with a VDO gauge because its the most accurate type of sender, being in the main body of oil.. a friend uses one with an autometer gauge because he was in the same situation as you (no sender) and hes tested it in boiling water and its accurate with autometer too.
next best alternative is drilling the oil relief plug for an autometer sender as thats in a decent oilflow. the sump plug type i dont rate as the oil is often static at the bottom.. you need it to be in the oilflow or else you'll get false, low readings.