I've built an 1982 El Camino for my daughter's first car. She loves it, but I have an a/c issue. It has been converted to R134A and cools well, but about 80% of the air comes out the dash vents, and the rest comes out at the floor. The factory service manual says this is normal. I'd like to find a way to get all the air out of the vents since its 100 here, and air at the floor is wasted. Any ideas on how to do this? I have all the factory manuals and plenty of old car experience, but this is my first G body car. All advice is appreciated.