Options to fix engine bay to fender seam

[Coelacanth]

While I was installing new fender splash shields on my '70 Charger, I noticed light shining through to the engine bay from inside the fender where there is a seam between the panels. The car originally had a large bead of black (or painted black) sealant of some sort, that is now decomposing and practically crumbling apart. I dug out the old sealer or whatever it was, so I can clean up the inside mating edges and try to fix or improve this area. I will need to unscrew a few of the mounting bolts in the engine bay where it bolts to the fender, but what are some options for re-sealing this seam, to at least prevent it from rusting (it looks worse than it is, the steel is good on the mating surfaces, just grubby)? I'm hoping I can straighten out the inner edge.

Not sure what this area is called, I'm calling it the "fender crease"; the same area on the passenger side of the engine bay has the same sealant bead, but at least it's straight and sealed properly:

 

[F4R/T]

Fill it in with the appropriate seam sealer, paint it and done. Mine had black that was painted as well

 

[Coelacanth]

Does seam sealer also act as a strong adhesive? Because I know it's not going to be easy to get those 2 surfaces to mate back up nicely...

 

[Project66]

I use Barrier Bond and I think it works well, but seam sealer is not there to bond the parts together. As the name implies, seam sealer is used to plug gaps and to keep air, dust, and water from blowing through. Superficially, seam sealer might help hold things together, but it's not a structural material (like modern panel-bond adhesives) and the joint will fail if you try to use it that way. The panels should be bolted or spot-welded to each other, then seam sealed and painted.

 

[Coelacanth]

I use Barrier Bond and I think it works well, but seam sealer is not there to bond the parts together. As the name implies, seam sealer is used to plug gaps and to keep air, dust, and water from blowing through. Superficially, seam sealer might help hold things together, but it's not a structural material (like modern panel-bond adhesives) and the joint will fail if you try to use it that way. The panels should be bolted or spot-welded to each other, then seam sealed and painted.

Thanks. From the looks of it, the engine bay side of the seam got bent out and no longer a flat, straight surface, then it was bolted on haphazardly. I imagine it was the guys who did the slap-n-dash body work decades ago because back then, I didn't know any better. I'll try and see if some careful hammering will straighten the inside edge more flat to match the fender edge.

 

[Coelacanth]

Here's a closer look at the fender crease area. I will remove some of the fender bolts, pull out the inside sheetmetal a bit and try to straighten it out. Once I get it to fit the fender side better, I'll clean it up and seam seal it back in place.

 

[Dave6T4]

I used paintable strip caulk. You can find it at most hardware stores, usually in plumbing or bathroom section. Squeeze it in the gaps with your fingers. You can smooth it out by wetting a finger, and dragging it along the caulk.