I am working on replacing both quarter panels on a 69 and have a few questions for the group. The door jamb brace is welded on top of the quarters at the rocker panel. How was this piece installed at the factory? Some had mentioned notching the new quarters to fit around it, but that seems like a hack job to me... Is the install order is quarter to rocker, door jamb brace on top...? What do you line the brace up to as you do the final welds? is it easier to plug weld these or use a spot welder?

i'm a little confused. what do you mean "door jam brace"? if you are talking about the area of the door jam that has the door striker and the vent in it, that is actually part of the quarter panel. but, if you are installing 1/4 skins, that area does not come with them as part of the panel.

I think you're talking about the brace underneath the quarter window that runs from the door jam down to the rocker. It welds to the rocker near the front of the outer wheel housing.
When I did mine I first plug welded to the door jam portion of the qtr. from the outside, then plug welded to the rocker by reaching through the access holes under the qtr. window. It's a tight fit and hard to see what you're doing, but I don't see any other way to do it.

yes, I am talking about the brace inside the quarter panel that the striker bolts to.

So far I haven't removed it completely, but it looks like I should... just looking for some other opinions.

yes, I am talking about the brace inside the quarter panel that the striker bolts to.

So far I haven't removed it completely, but it looks like I should... just looking for some other opinions.

Sorry, I was thinking of the diagonal brace inside the door jamb area. For the big brace, I had to replace it on my passenger side with one from a donor car. On the driver side, I did an 80% qtr., so I notched the area you're talking about.
The brace can come out, but it's hard to get to all of the spots on top of the rocker to replace it. Just depends on how you want to do it.