Curviloft skin over problem

Can’t get curviloft to skin over fender frame. Can anyone tell me what’s wrong with my frame?
Jim B
Matt 1926 car frame.skp (99.1 KB)

You’ve got a number of flaws in your geometry. Here are two of them.

The centerline at the rear end has a lot of edges crossing each other. Once you clean all that stuff up you should be able to proceed with Curviloft. The front corners are a bit problematic. Probably should be rounded off.