I JUST RESENTLY BOUGHT 1550 GAS AND I HAVE TO LOOK BETWEEN THE MUFFLER AND THE AIR CLEANER STACK TO SEE THE CENTERLINE OF THE HOOD FOR PLANTING CORN. ALL THE OTHER 1550s THAT I HAVE SEEN HAVE THE AIR CLEANER INLINE WITH THE MUFFLER. I SURE LOOKS FACTORY. WAS THIS DONE JUST A CERTAIN YEAR OR WHAT? I WAS TOLD BY THE SELLER THAT THIS TRACTOR IS A 1968 AND HE WORKED FOR OLIVER FOR 30 YEARS. CAN ANY OF YOU ANSWER THIS QUESTION FOR ME? THANKS DAVE MILLER