Access holes in B pillar - Ranchero

[jvo]

I am going to rebuild the whole back wall of the Ranchero.  Not happy with the rust here and there.  Its all flat stuff, easy to make, just have to keep it all in proper relation to each other.
Does anyone know the purpose of the access holes in the B pillar?  They are a couple inches wide, and 8 or 10 inches high, right behind the door.  I might not make these holes, just fill them in with a solid panel, unless there is a reason they are there. 
Also, there is an access hole in the inner panel also, between the front of the wheel well, and the B pillar, a little bit above the rocker panel.  I don't see any reason for that one either.  Can anyone shed any light on these?  I'm going to fill them if I can't find a good reason not to. Thanks.

[John Palmer]

Without a photo, It's just a guess.

If you look at most inner panels they are not flat.  They have holes, cutouts, and most important the have ribs pressed into them for stiffness.  Do the holes your talking about have ribs, or a bead rolled edge?  A flat panel of the same gauge is not as stiff as a formed panel.

[Limey57]

I know the holes you are reffering to and I guess they were punched out to save weight (the return flanges on them are to stiffen them up) but they may also have been for access for spot welding other adjacent panels.

[jvo]

The ones right behind the door latch have covers on them, put on with screws, and they appear to be from the factory.  There are some other "repair covers" that are definitely not factory, but these ones were not for weight savings, as they put the cover over the hole.  I agree with the stiffening ribs around the edge of the hole.  I can easily roll a few beads in them to stiffen them up a little, as I am going to make these inner panels about 2 inches longer than stock, to stretch the cab area inside a little.  I have to make up for the extra 4 inches or so of "Fairlane length" and a couple inches inside the cab, and a third inch on the B pillar should use up most of that.  The last little bit, I can inset the tailgate  a little to keep the bed length the same. 
I'll take a pic maybe and post it later. Thanks for the input.

[jvo]

Here are a couple pics of the holes in question.  I plan on adding two inches in the area where the masking tape is.  That is to move the whole back wall of the cab back to stretch the passenger compartment a couple inches as well as to keep the cargo bed the same size to take up the extra length of the Fairlane.
I am going to put the rest of this info into the build thread, so it doesn't get lost.

[57chero]

I remember using the holes to reach in and attach the nuts on the threaded trim clips for the check mark shaped stainless side trim behind the door. Originally there is a cardboard panel that covers the hole with a long metal trim piece a couple inches wide that runs up the edge of the door jam.

[Ford Blue blood]

Mine had the card board on the lower holes and metal on the B pillar.

[jvo]

Oh yeah.  Thanks a lot.  I never thought about the side trim on the exterior.  I guess I will be putting the holes back in again.  Appreciate that.