They make a flexable , paintable automotive seam sealer you could try, or just mix some body filler and spread it in the seam fairly thin with your finger and sand smooth , and DP over that.

well I forgot how tight the rails were on the 37 , I would just make sure I got a few good heavy coats of DP down in the rail to help against rusting, beings you cant get anything down in the rail to smooth out the sealer.

I am almost glad now mine were smashed flat and had to cut them off and make my own, as I hate sanding those hard to reach areas ...LOL

Hell I havent even worked on mine for 5 months, got burnt out on it . I'm almost thinking of getting rid of it as I dont feel like messing with trying to get a title for it , because the guy i got it from is going to jail for imbesslement , and I have no clue where he got it from, he said it was a trade. all I have is a written bill of sale from him. So I dont know what to do really

Spray