There's no trick, but it's a secret, remove the front seat first. It's kind of link taking you shoes off before you take your pants off, you don't have to, it just makes it easier.
Another thing to remember is to protect the carpet. Some plastic and an old towel on top to catch any coolant that may leak from the inlet & outlet tubes that you may want to tape up.
Nick Tiberio
FuryUs63
From: hemicuda472@xxxxxxxxxxxxx
To: "The 1962 to 1965 Mopar Mail List Clubhouse" <1962to1965mopars@xxxxxxxxxxxxxxxx>
Sent: Sunday, December 18, 2011 6:20:29 PM
Subject: heater box
What is the trick to removing the heater box on my 64 Savoy.