The Alaskan Project is almost complete, started engine today and O'Boy can't wait. My problem. The temp sending unit on the 1976 350 has a 1/2" NPT fitting in the stock head, the new ZZ-4 Aluminum head has a 3/8"NPT fitting, went and got an adapter but it hits the headers? I know there are ZZ-4's out there. What did you use? Is there a part that will fix me up? Can someone tell me the resistance range and maybe I can come up with something else? The dash guage is from 100 to 280 degrees. HELP I need to drive this car before it snows. Give a part number...Terry

Plug the hole in the head and drill/tap somewhere in the water jacket of the manifold.

I thought about that suggestion, too! Some intakes have a boss in them for the temp sender to start with.
Another idea, tho....Does your water pump have a threaded boss in it at the top? If so, you could put the temp. sensor there. Or, you can use a thermostat housing that has a boss in it to put the sensor in. The only problem with these ideas is, the temp reading will not be 100% accurate, because you're supposed to be reading the temp of the coolant in the head. It will be good enough, tho, as it will still give an indication of overtemp or not, and... you can "calibrate" the sensor with a resistor in the wiring. It requires an accurate measure of the coolant temp with a thermometer, or an infrared sensor. Then compare that reading to what the guage shows, and then install a resistor to raise or lower the signal to the guage. (It sounds a lot more complicated than it is!)

OK Guys, thanks for the help and ideas. I did a reroute of the fuel line and took out a 45degree fitting replaced it with a straight fitting and used the boss on the other side of the manifold, run the guage wire to the sending unit and I'm in business. Your the best, thanks from Alaska..Terry