Am trying to work on heater fan in my '53 Chev 3/4 T.--and it's darn cold up here.

Am I going to be able to get to the heater fan without removing the heater core? (It is a round core--) Or do I have to remove the heater core/fan as a unit?

At 7500 feet, it's cold up here with no heat!

Thanks in advance--T.K.