check your timming and check carb to make sure its not lean

those will cause it to run hotter

feel by hand the rad core when hot to see if you can feel cold spots on the rad...cold spots are where the rad is blocked

do you have a spring in the lower hose?

does it have the shrod in place?

is the clutch fan working properly?

yes a small hole will burp the air out and no need to run to temp and wait for the t stat to open to finish the fill

try some water wetter in it also...