[rghines1]

This should be C86 from the Nostalgiaair schematic:
http://www.nostalgiaair.org/Resources/139/M0013139.htm

This is an interesting thing Philco did. The two 0.15 caps are together to make 0.3 uF in parallel with the filter choke. This is a resonant circuit at 120 Hz (twice the line frequency) to further help reduce hum. You will want to stay close to 0.3 uf. The voltage across these caps is less than a hundred volts.

See if you can get three 0.10uf/400V poly caps in parallel inside the bakelite block to make up a 0.3 uf cap. Using 630V caps may be too big to get three inside the block.

Richard