mr gasket thermostat

[csx452]

Just bought a mister gasket thermostat for my 75 slant 6. I tried to install it and it won't fit. I placed it with the pill facing the engine but it is too large for the hole in the engine. What gives? It is the right part number. Any ideas?
Thanks,
Frank

 

[Longgone]

Your thermostat housing may have been changed or you may have the wrong thermostat. There are two sizes for the Mopars, you might have to swap it for the small one.