Rusted headlight eyebrows are common. The explanation I got from my Grandpa ( he had one when it was new ) was that mud would get kicked up off the tires, and pack in between the headlight and the fender and rust the fender from the inside. The other common spots are the cab corners, driver and passenger floorboards, and the front of the rear fenders. That truck looks pretty solid. I had almost a foot of metal missing in one of my cab corners. Check out the earlier pics in my build thread as mine had rust in all those areas. I drove my truck for almost 5 years with a 261 - 6 cylinder and the stock 3-speed and rear end. The column shift was wore out so I put a Hurst truck shifter on the original transmission. Biggest problem was the the rear end had the stock 3.90s in it which meant it would top out at around 50 MPH.