The 1927 studebaker im working on has a funnel located near the fan,takes the air and blows it past the exhaust and then through registers in the floor. Im positive many people suffered poisoning from that setup. It will look intact but wont be passing gas so to speak.
What im getting at, is any fumes generated under the hood such as vaporized diesel fuel,exhaust and battery gassing could also be lethal. Glad you are goin for the less prehistoric method.
I have been thinking about something for a while-in floor heat.while ridiculous at first, dry floor and warm feet,solves two big problems for me. Could heat the seat too, maybe i wouldnt need a cab after all....