Vintage Air Cowl block off help

[lts70]

I just put in a Vintage Air Ac system. The kit has you block off the passenger side vent and supplies a plastic plate to do so. On top of that because I installed a custom unit in order to shave the fire wall I had to cut through the cowl system to run my lines and bulkhead. I cut through where the old blower motor goes. So even though I have the vent covered over I have a hole about the same size of the vent cut open that air blows through with no way to plug it off with out some how shutting down that side of my cowl system. Has anyone done this or have any idea of the best way of going about blocking air to the passenger side of my fresh air system? I will see if I have some pictures to show you what I mean. I will try to take some better ones that show the actual hole tonight after work..