Ok!! Don't laugh....stupid question

[mcubedntx]

Ok!! I have this 69' and I have had it for 4 years, but recently moved into a new home and now I have a 20 X 44 shop, so I have been taking my truck apart piece by piece. The bed is off, the hood, the cowl, and if my 3 year old was Bam-Bam the front sheet metal would be on the ground. I removed the passenger side rocker panel tonight and while I was messing around I noticed that the vents in the kick-panels are sealed off by the front of the cab. For some reason I thought the vents would be exposed when I removed the frontend. Both are badly rusted and I had planned on just sealing them off with some sheetmetal, what are the ramifications if I seal these off? Are they to recirculate air? if so can I create my own vents? Also does anyone have a cut away of how the air circulates thru the dash? Is there a way to get a rustproofing product in this area ie: Zero-Rust or POR-15?? I want this done right and I am affraid I will have to remove all the spot welds to gain access to this area. Thanks for any and all advice