<VV> vermin in Corvair engines

[shortle]

Changing the automatic diff. (intermixing) in my Rampside, I noticed a bunch of dry dog food in my heater. Then with the engine out, I looked into the top of the engine I saw quite a bit of it. I pulled my oil cooler cover and could not believe how much was in there (I just drove this vehicle 1400 miles to Kansas and back). So now I have the engine (shrouds) all apart and am wondering what can I do to keep the mice out of my cars. Anyone? Thanks all.
Timothy Shortle in Durango Colorado
On my way to Palm Springs in a couple of days, hopefully in the Rampside