Update:
The hood vents were molded shut, so I decided to open them. I managed to brake one of the "fins", so had to replace it with sheet styrene:
Confronting decals and reference pictures, I decided that this version had no lower front air intakes, so I closed them with plastic sheets, and sanded to shape:
That orange stuff is homemade putty: tamiya extra thin cement and plastic sprue mixed in a glass cup:
I still don't know how good it actually works, but I gave it a try this time, because Tamiya basic putty bleeds throught the primer I intend to use....
I also covered the hole in the floorpan with (again) styrene sheet, and completed the chassis member with styrene strips:
Thanks for looking.