I recently bought a 78 1440. The previous owner added a rock trap but didn't add the cylinder extensions. It wasn't a problem for him since he didn't have any head carts and combine never left his farm. My problem is that I can't raise the head up far enough to hook and unhook heads. I have looked up the part number and there are two different ones. One is 8.27" long and the other is 12.23" long. My feeder house is 47". The part books calls for the 8.27" with 47" feeder house with rock trap. The factory extensions currently on it is 6.5". I feel like the 8.27" extensions won't add much, but the 12.23" extensions might create a bind when raising the head. Which one should I get? Anyone have any experience? Sorry for the long post, but any help will be greatly appreciated.