That heater in the 1951 Accessory Installation Manual is an oddity (enigma)? (part number 986544)
It is not shown or referred-to in the 1951 Truck Data Book (October 15 1950), which shows the:
1. "Outside-Air Ventilator, Heater and Defroster"
which is also referred-to as the "Fresh Air Heater"
but it is listed in the Price Information booklet as "Heater, Airflow and Defroster" for $59 (January 10th 1951)
Just to further confuse, the CHEVROLET ACCESSORIES for 1951 PRICE LIST of November 15 1950 contains:
"Heater and Defroster - Air Flow" $59.00 (part number 986104 - same number as listed in the Installation Manual)
2. "Dash Recirculating Heater and Defroster"
which is also referred-to as the "Recirculating Heater"
but is listed in the Price Information booklet as "Heater, Dash-Type De Luxe w/Defroster" for $35.50 (January 10th 1951)
Just to further confuse, the CHEVROLET ACCESSORIES for 1951 PRICE LIST of November 15 1950 contains:
"Heater and Defroster - Recirculating" for $35.90 (part number 986248 - no shown in the Installation Manual)
