I would like to close off the cowl vent on my '53. How have others done this? Use the existing vent plate? New metal? Why? Because I think it would look better for my build.

 

I have done this on mine you will need to make a replacement piece as the vent would need to be added to all around making it easier to make a new piece . I am also eliminating my vent windows also for looks . This however creates cab venting problems . I am using the right side vent through a fresh air heating system and may consider installing a matching one on the drivers side along with installing some one way venting in the back wall of the cab from a newer auto to get some air movement for when the AC is not needed just some flow . PS my 35 dodge has a functional front vent and the air flow is amazing but keeping it sealed is difficult resulting in allot of replaced stereo equipment .

 

Looks like the same thing I am going to be doing. I have eliminated the side vents already. Cowl will be gone. Need to take the cab off for that so I will be filling in all the holes in the fire wall at the same time. I would like to delete the vent window as well. Going to use a Vintage Air system for ventilation.

 

Yes but you will still want outside air from somewhere .

 

I used the original vent and filled the front gap with 1/4 inch square rod. Filled the other gaps as needed and welded in place.
Pic shows what it looked like when I first tacked it in place...



Here is what it looked like when painted...

 

Charlieled, wow sharp looking cab. After you tacked the vent closed did you go back and using 100's of tacks fill in the rest of the gap? Sorry if this sounds dumb, I'm learning as much as I can about metal working as it is new to me. For your firewall did you cut out the original one and make that one? Looks amazing.

 

Yep, lots of smaller welds to fill in the gaps in the seams. The vent panel is fairly stout given the thickness of the metal and the bends that stiffen it but care must still be taken not to warp the cowl.
The firewall is a one-piece replacement for the OEM. I had Direct Sheetmetal cut/bend the firewall for me...they asked if they could use my design for their product line so if you would like one it can be purchased from them directly or from other vendors I have seen on ebay and elsewhere.