I don't know how hard you have to slam the door, but if you don't want to have to slam it, you can move the striker outward a smidge. Once the foam squishes into place over time, then move the striker into the correct position. I did that on mine and it worked nicely.
Carl

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission