Does anyone know the cool (compressed) stock thermostat height and how much it's suppose to expand when heated?

Is expansion limited to bracket size?

Check your Haynes manual; it has the hot and cold lengths in there.

IIRC, the fully-expanded thermostat does not reach the edge of the bracket.

--DD

Yes expansion is limited by bracket, but with proper cable adjustment it is all you need to open the flaps. The bellows should be fully compressed when cold and start opening at 185 -194 degrees F.

Here's a thread I wrote a few years back. Lengths/temps included.