Technical 55-59 cowl vent

Hey guys on my 56 Chevy truck, my kickpanel vents are gone and all butchered up. I was wondering if I replace the cowl vent(that’s right on top of the cab and below windshield) with a cowl vent with no holes, will that block the air coming inside? At higher speeds I have a wind tunnel and I’m trying to eliminate that. These are the pics of my kickpanel vents. Hope you guys can help. Thank you