273 overheating after new timing chain set and waterpump

Pictures would be a great start.
What does 1/2 or 3/4 equate to in Fahrenheit?
Is it actually over heating to the point of releasing pressure from the cap?
Have you temped it with a temp gun?
Have you looked into the radiator to see if there is circulation?(dont remove a hot cap please)

You live in Canada and you really think the pump is going to make that much of a difference.