Sentsat Ed, you got the years about right. Hall gave it a go but the two fans were powered by an auxiliary 2 cylinder two stroke engine. The BT46B was a single fan and powered off of the Transaxle. In theory, all you had to do was lower the air pressure under the car .18 pounds and with the square inches you would get 900 to 1000 pounds of static down force. Talk about superglueing a car to the track. The BT46B proved the theory worked and I doubt you could get anything like this past tech today. Many don't understand this concept. The fan does not "Suck" the car to the ground, it lowers the air pressure under the car. The air that exits the fan is only at 55 mph or less and exits in a radial pattern, not a column. It will not pickup rocks, clods of dirt or anything large, just some dust maybe. I feel that the BT46B design by Gordon Murray was genius. His out of the box thinking stood F1 on it ear and made every team jump through hoops to catch up. Gordon proved it works, I just don't know how well it would work on a stocker. There may be too much open area in the fenders to gain enough lower air pressure. Who knows? If it did work, you might see some 230+ laps at Daytona. 'Ol Smokey Yunick understood what went on under a car. I bet he could have made it work.