Slight frame crack. Opinions?

This morning we gathered up all the new suspension parts and the POR15 package that was delivered earlier this week and my son and I drug our weary bodies an hour away to my brothers house. And I was immediately upset when we got there and realized we had forgot the camera. Anyway, this is where we were sandblasting all the areas of the engine bay that we couldn't cleanly strip with chemicals and blast the underside of the fenderswells and frame. This is on a '73 Duster 340 car. We had discovered a repair on the passenger side frame last week when dropping the K Frame. We only noticed it because whomever did it did a half *** job and didn't grind the weld down afterwards. It's a very small repair, 1/2" to 3/4" tops. After all the sandblasting and blowing the sand out of cracks and crevices my brother spotted another crack (not repaired) in the same area on the opposite side of the car. The crack is on the bottom of the frame right underneath where the upper bumpstop mount is welded on. Again, this one is 1/2" to 3/4" tops. It was decided to weld this one up and grind both down before primer was sprayed. I really don't think this is going to be an issue, but wanted input from any of you that have experienced this. Being new to Mopar and still learning, my first thought was that this happens and it's normal. I called my Go To Guy for everything Mopar and he wasn't able to be reached. My brothers car ('67 Barracuda) does not have these same cracks. So, is this normal? Or should I start cutting off the front end and start bending tube frame right now? Certainly some of you have seen this happen. We had a few other sheetmetal surprises today on the drivers side fenderwell (My brother ran into the exact same thing on his '67 Barracuda), but nothing that is structurally effected and we can't repair with a little stitch welding. Also one of the mounts for the K Member got blown out when my son was sandblasting. That's an easy fix. So not a bad day all in all, except we forgot the camera and we can't post pictures until next weekend.