Wondering what the operating temp should be on a 90 GM with a 305. In the winter mine doesn't hit the 100 mark on the gauge which would be the centre of the gauge, seems a bit harder on fuel in the winter also which has got me thinking. It runs about 75 degrees celsius.

 

It's harder on fuel in the winter because winter gas is different than summer gas and it will always be a little thirstier for the winter stuff