I Had a Porsche 914 some years ago and learned some things about air flow. The 914 being a mid engine car needed clean cool air to the engine cooling fan. They had a strip of plastic running across the bottom of the car right before the firewall and engine compartment. It was about 2.5" wide. I asked and learned that this strip was an air dam to create a low pressure area directly behind it thus allowing the cooling fan to draw clean air over and through the engine heads and cylinders. If you did something like this it may do the same thing and allow the air to flow to and through your radiator if you locate it in that area. You may need to run the electric fan all of the time to keep the temps. within range to make it work but it should work. I would try your plan I think it may work using the air dam across the bottom of the car. They used a semi rigid material (plastic landscaping edging) that could bend if something hit it but not break off. I looked for pictures of this air dam and couldn't easily find any. I think many 914's have had it removed or knocked off before or during restoration but believe they came from the factory with one. I know my race shop mechanic installed one my car and the engine temps dropped and he is the one who educated me on it. Good luck and thanks for taking us on the journey with you.