[njsteve]

OK, I kicked the wife out of the kitchen and did a little experimentation on the stove with a pot of water, a candy thermometer and a digital ohmmeter. Here are the results:

80 degrees: Wells at 650 ohms, LL at 573 ohms
90 degrees: Wells at 526 ohms, LL at 445 ohms
100 degrees: Wells at 429 ohms, LL at 365 ohms
110 degrees: Wells at 328 ohms, LL at 266 ohms
120 degrees: Wells at 283 ohms, LL at 227 ohms
130 degrees: Wells at 250 ohms, LL at 200 ohms
140 degrees: Wells at 216 ohms, LL at 170 ohms
150 degrees: Wells at 198 ohms, LL at 155 ohms
160 degrees: Wells at 173 ohms, LL at 133 ohms
170 degrees: Wells at 157 ohms, LL at 119 ohms
180 degrees: Wells at 135 ohms, LL at 101 ohms
190 degrees: Wells at 120 ohms, LL at 89 ohms
200 degrees: Wells at 109 ohms, LL at 79 ohms
212 degrees: Wells at 104 ohms, LL at 75 ohms

And as a result of my weekend TempSender-Palooza, I am going with the Wells sender as the one that makes my temp gauge far more accurate when it comes to reading what the coolant temperature actually is, as corroborated by an actual thermometer as well as a mechanical temp gauge. (That is, until the original GM unit arrives)

I will update with the original GM sender when I get that. The original ones have the part number stamped above the threads. The later GM ones have no part numbers whatsoever and seem to be a generic replacement.