I know this is probably not going to help you but the dark siders might find this useful.
The LS1 uses an aluminium sump. Some models have a sump heater which is a ceramic element in the side of the heater to stop the
oil freezing up in icy cold climates. This can be unscrewed and thrown in the bin and your
oil temp sender screwed in. I'm running Autometer mechanical guages so I machined up an adaptor to fit the Autometer capilary fitting directly into the sump. It seems to work really well. No leaks so far and an accurate reading on the
oil temp in the sump.
Cheers