Edelbrock Intake Issue

I have the Billet Specialties 98020 thermostat housing and the Emp Stewart 305 thermostat. The issue I am having is when I installed the thermostat housing and thermostat, I noticed that the thermostat is not clamped down tightly in the housing, it wiggles around slightly.

Does anyone know if this will work ok or does anyone know of a thermostat that fits more snugly or is this normal with the Billet Specialties housings?

Billet calls for a Stant 45478 which I can't seem to find locally.

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