I am trying to remove a heater from a 1954 pickup. It is the type of heater depicted here:
53-55 Fresh Air Heater

The problem is that I've removed all the mounting hardware that I can locate, yet I cannot get the heater loose. I am obviously missing something.

All hoses are disconnected. The thermostatic valve has been dismounted. The nuts have been removed from the two studs through the firewall. The three clutch-head screws on the side of the duct that faces the passenger have been removed. I cannot see or feel any corresponding screws on the opposite side of the duct toward the firewall. I can wiggle the whole heater slightly. If I tap on the studs from the firewall side, they deflect freely, then 'spring' back to their original position.

Any suggestions where the mystery mounting hardware is?

Thanks!

-Kevin

This is what happens when you live with a house-full of women, the wife and daughters name all the cars:
1960 Impala - "Frankie" (Frank Sinatra)
1961 Apache - " 'Mater Jr." (wrecker)
1965 Corvair Monza Convertible
1967 C20 "Ol' Blue" (hidden in a log cabin for 30 years)
1972 SuperBeetle Convertible - "Juliet"
1976 SuperBeetle Convertible - "Olaf"
1988 Alfa Romeo Spider Veloce - "Romeo"