Here's what I have for bolts. The therm housing ones are 5/16-18 but i'll need to measure to see which lengths they are.
7/16-14
1 3/4" long -
91271A671
5/16-18
3/4" long -
96242A631
9/16" long -
96242A630
1" long -
91271A671
1 1/2" long -
96242A633
2" long -
96242A648
3/8"-16 SS bolt
1" long -
96242A736
1 3/4" long -
96242A746
1/4-20 Stainless
1" long -
96242A509
1/2" long -
96242A502
3/4" long -
96242A506
I beleive the T-stat housing bolts are the 1" and 1.5" long bolts under the 5/16-18 header, but i'll have to double check. Mcmaster only has the stainless ARP bolts. I haven't found them to carry the black nitride bolts, and can't find the matching washers. But if you plug in some of those numbers it brings you to the entire chart to order bolts by size. Obviously the more you order to break up shipping cost, the better