Large Style Thermostat Housing

Thanks for the replies

I ordered the dorman housing with mixed reviews.

I am trying to find a thermostat. The hole in the intake measures 2 1/8. I have a couple thermostats from over the years and they measure measure 2 1/8 and fall through the hole

Searching though summits website using years 1968 and 1983 the same part number thermostats come up
This should be easier but I’m missing the boat somewhere