I have to agree with the comments so far. I like your Dad's build and yours is coming along nicely. And that firewall is outstanding. I have an Orange '40 Coupe in progress, makes me wish I'd seen your firewall before I painted it!
The firewall was created by cutting away the left and right bulges, but leaving the flat center area. I then added pieces taken out of the recessed firewall found in all of Revell's modern '32 Ford kits (white portions). In the center of the modified firewall, you should be able to see there is a horizontal parting line. A rectangular piece of gray plastic was added below the original flat area to bring it down even with the new white areas and an eyebrow cut made to clear the engine/trans. After that is was filler, primer, sand, primer, sand, primer, sand.