If you were pulling a 21 ft disk with a 1456 in Hi 2nd you must have had it up on its wheels. My brother bought a 1456 in time for the 1978 crop. I drove it the first year we had it pulling a 20 ft. IH 475 disk. If I let it down Lo 4th was the best it would do. I could run in Hi 1st if I was just incorporating Treflan. It didn't pull that disk any better than the Ford 9000 we previously had in front of it. It also had a Hiniker cab on it. Had to really turn up the radio in order to hear it and the a/c didn't work more often than it did. It had a York compressor that was a genuine piece of junk. I hated that tractor so much that the next year I made a deal with my brother. If he would put it on the planter he could drive it and I would go back to the 9000 with just a canopy, no cab. After that the York compressor somehow disappeared and a GM compressor replaced it.