[Ron Ramirez]

My question; where was plant number 4 located?

Between Ontario and Westmoreland Streets in Philadelphia, with C Street bordering it on the west. Plant 4 was Philco's own in-house cabinet factory, part of the Philco complex in Kensington, most of which is now gone. McVeigh Recreation Center now occupies the site where Plant 4 once stood.

http://www.philcoradio.com/history/hist9.htm
(scroll down to see a map of the old Philco complex)