67-72 Electric speedo

[68c10airstream]

Hi Curt, ls1nova is correct on drilling the head for the original sender. I was reluctant and my water pump has a nice flat boss on the forward area that worked great. As i've stated in prior posts that when i was done my temp gauge read about 3/4 scale as the LS runs hotter than my original 68 small block. Once it was installed and at 3/4 scale i cut the wire close to the sender, temporarily installed a variable resistor and dialed in some additional resistance and dialed the temp gauge back to 1/2 scale. Removed the resistor and read the value. It was 4 ohms, so i soldered in a 4 ohm, 1/2 watt resistor inline. All is good!