Well if he's tried it before, he's probably not going to budge. You could always try convincing him that the Chevys are so poorly welded that there's no way to keep the air flowing through the cowl.
He's usually a stickler for having everything functional. I was surprised when he didn't mind having all those dash vents non-operational. Despite his claims that it'll be a daily driver I imagine it'll never see rain, snow, or cold weather. That Chevelle he had was no fun in the Winter.