While the weld in bung would be better, I like the quick simpleness of taking out the drain plug and replacing it with a hollowed out one that will accept the sender. I'll have to check and see if the plug in the pan is a 1/2"-20. That seems to be a pretty universal size, so it probably is. The other easy option would be at the return line up by the cooler that's mounted on the radiator, but I would need a T that was -6AN male/female with a female 1/8" NPT and I can't seem to find that.