[Ron Ramirez]

...later this evening...

I would have to see more, better, larger photos before drawing a conclusion. I would need to see:

• underside of the 51 chassis
  
• the gold sticker on the back of the 51 chassis (does it say "Model 51" or something else?)
  
• the back side of the front panel, and the shelf the upper chassis sits on
  

Based upon the photos shown in that thread, I wonder if that 51 chassis was modified at the factory, or after the fact? It would have to have a larger power transformer with a heavier current capacity to power itself plus that modified* Model 4 SW chassis.

(* - modified in that these SW converter chassis do not have a separate 80 rectifier or power supply as the stand-alone Model 4 SW converters have; they draw their B+ and filament voltages from the radio above)

On the other hand, if someone took a 470 or 490 and added that 51 chassis after the fact, then someone did a very good job of making that panel.

Knowing how Philco has Phooled us before with undocumented, very low production Phactory Phranken-Philcos, who knows...

Edit: It seems to me that someone has mentioned owning, or having seen, a set like the one in question before. Yes! I remember! It was a Phorum member who I haven't seen on here in a while...