Hi Lee, the fan remains one of those mysteries - shape is similar to the Moplen part but no real match. 8MA1010 has the common early type fan blade, which has "3763475\11" on the hub but no other significant markings.
The fan motor is easier....clearly marked Motorcraft F-18527-AA. I have never found an EXACT match but there are a lot of versions out there, with different details. IIRC late 60s Econoline vans are a good potential donor. Some versions have the hole in the body (as the Goose does) and other don't (these might be designated with -AB vice -AA). It appears DeTomaso shortened the carriage bolts to 90.0mm (for clearance) and possibly added the aluminum adaptor that holds the fan. Definitely a crazy assembly...I found it hard to believe originally that the motor attachment method was a factory feature.
Anybody know if 60s Fords had heater fans that looked like the "3763475\11" part in Lee's photos?! Regards, Nate