Follow up question - does the inner cowl need to be plug welded to the inner-to-outer cowl? I got my inner cowls in solid with door pillar and kick panel now, but there is a 1/4" gap between the inner cowl and the inner-to-outer cowl. Are plug welds needed for strength or can I leave and fill the gap?
Kind of an ancient thread, but my opinion is that you should weld the inner cowl to the inner-to-outer cowl. It provides some strength to connect the outer cowl to the floor and toe panel, and keeps road crud from getting in the gap (although you could fill that with sealer). The inner-to-outer is infamous for not fitting correctly. What I did was modify it so that it fit better and I could weld everything together.
You could put a few chunks of metal in there to connect the two and then use sealer to fill the gap. It'd probably work OK.
