On casting 329835-1
91 or early 92 70

Bowl is the same width at 2.120"

Depth from surface is way up at about 0.620" ( sst .440" min )
Thats a chunk of change
Thats enough to make the area at the thermostat too thin so maybe it is a different casting on the sst
The chamfer into the bowl looks very small on the sst rules drawing and my stock one would look the same if you milled it down that far.

Powerabout