Have the same " gap " on my '40. Too wide for standard fender welting to close. I thought it would be a problem keeping mud & dirt from splashing up on body - hasn't been an issue at all ( although I don't drive the truck in the wet weather too often ) I don't think there was any filler there on stock / original trucks.


1940 Chevy KC 1/2-Ton
In the Stovebolt Gallery