I notice on Ebay and other sites (SSdiesel) that the thermostats cost over $30us. I thought that was a lot so I looked at my local parts store (Canadian Tires) and they have them in any temp for only $10 can. They are fail safe as well. Gaskets are $2.99can so check your local parts store before ordering online.

I bought mine from a supporting vendor here at the diesel place, Kennedy Diesel, for I think $10.00 bucks each for the Robertshaws too, who many think are the best thermosat maker. I did buy my seals locally cause I didn't know they didn't come with the stats.

I bought my robershaws from kennedy as well $10 each (gaskets autozone .99 each), when I installed my 97+cooling system. 96 was the change over year from single to dual. The single used a bypass close-off valve system, that's why its more expensive than normal t.stat's. When GM went to the dual system they abandoned the by-pass closure sytem(using normal t.stat's), which lets the system by-pass all the time, but when the t.stat's open the coolant flows through the larger circuit.

The more expensive ones are the 180° because they are harder to find and the local big chains don't carry them anymore. You can still get a 190-192° from the locals for the same cheap prices as always.