I am working on a 1970 fastback that I am going to install a Classic Auto Air air conditioning system in. That said, this system doesn't use the fresh air intake from the cowl and comes with a plate to actually cover it. That means that the only thing that would use the cowl as an air intake is the kick panel vents. With air conditioning I don't see where I would ever really need those. I am considering covering the holes in the cowl. The part I'm talking about is the part welded to the uni-body, not the screwed on cowl cover. What I'm concerned about, which may be me just being paranoid, is the wiper motor and whether it needs this open to keep the motor cool. The covers I would make would be removable in case I ever needed to take them off. Do any of you think the wiper motor would need the air for cooling or am I just being paranoid?? I personally think I'm being paranoid especially since the car would actually only see rain if I got caught somewhere, but that wouldn't be the time to find out.
Closing off the hats in the cowl wont effect the wiper motor,you should be OK. Let me know how the install goes,I may go that route with my 70.Also which unit do you plan on installing?
Not exactly sure why you'd cover those unless your cowl is rusted out. But in any case - I covered mine on my 1970 because cowl is rusted out. No problem with wiper motor - althought only caught in rain a couple times for short periods of time. I do plan on fxing my cowl this winter though and will open back up.
dnswwood, I'm planning to use the Classic Auto Air system that is made for the 69 and 70 mustang. You can see it here. http://www.classicautoair.com/Mustang6970.asp You can get the install instructions there too.
Palerider, If I put in the air conditioning system and the only thing that would still use the cowl openings is the fresh air vents in the kick panels, why not eliminate the potential for collecting water, leaves, dirt, and other crud? I had a 1970 mustang years ago and I don't think I ever used those fresh air vents anyway. If I do plug the cowl, I would also cover the rectangular drain holes in the bottom of the cowl forward of the doors to keep varmints out too. I live in the country and certain times of the year the mice converge on homes and get into any place they can. As for my cowls, they are not "rusted out" and are pretty solid now but they did have pitting and a few pin holes inside. I opened them up cleaned and fixed them and treated what rust was there, but I'm thinking if there aren't any openings, then the rust can't grow any more. There were varmint nests that would fill a coffee can inside the vertical part of the cowl sides. Like I said, the covers would be removable and only held in by a few screws so going back would not be a problem.
It just occurred to me that if I plug up the cowl I can put audio system speakers in the kick panel right where the fresh air vents go. No hacking of doors or kick panels, or buying anything, etc. This just keeps getting better.
I've wondered why people don't just cut out the rusted parts and put solid steel in there. I see no reason for the cowl vents since I'll never open the vents. I'm not talking about the one between the hood and windshield, but the ones under the cowl cover.
Anybody ever just made them solid, as a long-term solution?
Yep. That's the plan. I'm going to cover the holes in the cowl that is under the cowl cover. Then when i paint, it will get semi-gloss black under there. Like you said, I never used the fresh air vents on the 70 Stang I had years ago. That's why the windows go up and down.
I've got 2 1970s - One with cowl vents covered because of rust issues I mentioned. I also have speakers in kick panels. Speakers really do not cover up vent openings. The other 1970 I have has a solid cowl with fresh air vents operable.
I prefer having fresh air vents open. Quite a bit difference than opening just the window. In any case, would keep cowl vent uncovered if cowl is solid. Put air in as planned and pour some Por-15 down cowl openings to help prevent any further rust. Just my preference not that big of a deal either way.
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1970 Cowl question - 
