39 merc Conv. help

[SuperDave]

Most of my experiences in restoration has been Model A fords (Got my first one in 1956). I have worked on a 33 and 39 ford , so I am not entirely clueless! LOL. This is a 116" WB Sport convertible.. ? It just arrived at my shop on a roll back. A restoration was started in the early 2000's. The owner that started the resto. is unknown. Body off with all paint and body work done. Many (damn near ALL) small parts missing. My job is to get it running and brakes working. I'll let the restoration shop worry about all the exterior and interior trim. As an example: No front brakes at all, just spindles.There is nothing on the firewall but many holes. I can guess at a few things, but a picture of the engine side of a 39 Merc. firewall would help a lot. Aside from body parts, how much of the mechanicals (Brakes-engine accessories) are interchangeable with a 39-40 Ford? Any other reliable parts sources other than Dennis Carpenter and Mac's?
Thanks guys and gals.