The question comes up a lot about the part number for the 180F stat for the single stat crossover.
I recently swapped my 195 out for a 180 as the 195 was beginning to get hinky and not open until over 210.

The GM number is 19114512 and the AC Delco number is 12T45D

This stat should fit all the single stat crossovers on the 6.5 TD
I have it in a 95

This stat open nicely at about 180F and the temp may reach 190F before it starts to drop off again.

A nice little tidbit

Best

Robyn