Those creases would indeed change the shape of the top of the fender. It would be hard to know where to put any creases to help the fit. Putting in a crease would make the top edge of the fender a bit higher at the point of the crease by essentially shrinking the flange. You could try it and if it doesn't help, flatten the creases back out. A crimping tool for sheet metal ducts would do the trick if you want to try. Crimper
But I'd try Carl's suggestion first.

Last edited by klhansen; 03/21/2020 6:50 AM.
Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.